From Ukraine, ITV News correspondent John Ray reports on the latest developments.
Russian President Vladimir Putin has ordered a partial mobilisation of reservists in Russia, effective immediately - plans that have been condemned by Joe Biden and other world leaders at the UN general assembly.
In a move that is seen as a significant escalation by Putin, it follows humiliating setbacks for his troops nearly seven months after invading Ukraine.
It’s the first mobilisation in Russia since World War II and something Western backers of Ukraine derided as an act of weakness.
President Putin stressed that mobilisation would be partial - saying that only Russia's reservists would be conscripted.
Russia already has national service, with many spending time in the armed forces for around twelve months, between the ages of 18-27.
Putin said he has signed a decree on the proposals, and that conscription would start on Wednesday.
Speaking at the United Nations General Assembly, US President Joe Biden declared that Russia had “shamelessly violated the core tenets" of the United Nations charter with its “brutal, needless war” in Ukraine.
Delivering a forceful condemnation of Russia's invasion to the international body, Biden said reports of Russian abuses against civilians in Ukraine “should make your blood run cold.”
He also said Russian President Vladimir Putin's new nuclear threats against Europe showed “reckless disregard” for his nation's responsibilities as a signatory of the Treaty on the Non-Proliferation of Nuclear Weapons.
Mr Biden added: “We will stand in solidarity against Russia’s aggression. Period.”
He also criticised Russia for scheduling “sham referenda” this week in territory it has forcibly seized in Ukraine.
The announcement from Mr Putin was slammed as "dangerous and reckless" by NATO's secretary general Jens Stoltenberg, stating that while the mobilisation is not a surprise it will serve to escalate the conflict that began with Russia's invasion of Ukraine on February 24.
In an interview with Reuters news agency, Stoltenberg suggested "that the war is not going according to his [Putin's] plans," and suggested the President had made "a big miscalculation."
“We are talking about partial mobilisation, that is, only citizens who are currently in the reserve will be subject to conscription, and above all, those who served in the armed forces have a certain military specialty and relevant experience,” Putin stressed.
The total number of reservists that will be drafted in the partial mobilisation is 300,000, officials said.
Putin said the decision to partially mobilise was “fully adequate to the threats we face, namely to protect our homeland, its sovereignty and territorial integrity, to ensure the security of our people and people in the liberated territories.”
His speech comes after significant Ukrainian military success over recent weeks, with a counter-offensive driving Russian troops from parts of the Kharkiv region. Ukraine claims that hundreds of soldiers have been taken prisoner.
Shortly after Putin’s address, Russian media reported a spike in demand for plane tickets abroad amid an apparent scramble to leave despite exorbitant prices.As protest calls circulated online, the Moscow prosecutor’s office warned that organizing or participating in such actions could lead to up to 15 years in prison. Authorities issued similar warnings ahead of other protests recently.
The state communication watchdog Roskomnadzor also warned media that access to their websites would be blocked for transmitting “false information” about the mobilization. It was unclear exactly what that meant.
Within hours, police arrested scores of people at antiwar protests across Russia, including at least a dozen in Moscow.
Russian Defence Minister Sergei Shoigu also gave an interview on Wednesday in which he confirmed that only those with relevant combat and service experience will be mobilised.
He said there were around 25 million people who fit this criteria, but claimed only around 1% of them will be mobilised.
He specified the number of conscripted reservists would total 300,000, but added this would be a "one-time" boost of personnel
Shoigu also said that 5,937 Russian soldiers have died in the conflict, far lower than Western estimates that Russia has lost tens of thousands of troops.
Speaking on television, the Russian president also expressed his support for referendums scheduled to take place in parts of Ukraine that have been occupied by his forces.
The UK, US, and other allies have already said such referendums would be a "sham" that would have no international legitimacy.
The referendums, which have been expected to take since the first months of the war, will start Friday in the Luhansk, Kherson and partly Russian-controlled Zaporizhzhia and Donetsk regions.
Ahead of the announcement, Ukraine's President Volodymyr Zelenskyy said there were lots of questions surrounding the announcements but stressed that they would not change Ukraine’s commitment to retake areas occupied by Russian forces.
“The situation on the front line clearly indicates that the initiative belongs to Ukraine,” he said.
“Our positions do not change because of the noise or any announcements somewhere. We enjoy the full support of our partners in this.”
The Prime Minister Liz Truss has yet to comment directly on the latest developments, but did tweet an image of herself with the First Lady of Ukraine Olena Zelenska and Prime Minister Denys Shmyhal.
She said she reaffirmed to them "Britain's steadfast support for the Ukrainian people as they fight to restore their sovereignty and territorial integrity."
The president of Latvia, a nation that shares a border with Russia, condemned Kremlin aggression in Ukraine while speaking at the UN general assembly.
Egils Levits stated that Russian rhetoric has become increasingly hostile towards neighbouring countries, he said: "Promoting the idea of the supremacy of Russians and their special missionary role in the world are all contemporary expressions of racism - that is exactly the opposite of what the United Nations stands for."
'I'm not bluffing'
In closing references to potential nuclear conflict, Putin concluded his address suggesting that the West was engaging in "nuclear blackmail" against his country.
"Our country also has various weapons of destruction," he said. "With regard to certain components they're even more modern than the NATO ones. If there is a threat to the territorial integrity of our country and for protecting our people we will certainly use all means available to us."
"I'm not bluffing."
Putin's address to the nation was meant to take place last night, at six o'clock UK time, but was delayed. No reason was given.
"A tragedy for the Russian people" - Zelenskyy spokesperson
A spokesman for President Zelenskyy called the mobilisation a “big tragedy” for the Russian people.
In a statement to The Associated Press, Sergii Nikiforov said conscripts sent to the front line in Ukraine would face a similar fate to ill-prepared Russian forces who were repelled in an attack on Kyiv in the first days of the invasion in February.
“This is a recognition of the incapacity of the Russian professional army, which has failed in all its tasks,” Nikiforov said.
President Zelenskyy could address the developments in his daily address to the nation tonight.
"Admission his invasion is failing" says Defence Secretary
The UK's Defence Secretary, Ben Wallace, has described Putin's announcement as an "admission his invasion is failing."
“He and his defence minister have sent tens of thousands of their own citizens to their deaths, ill-equipped and badly led,” Wallace said in a statement.
“No amount of threats and propaganda can hide the fact that Ukraine is winning this war, the international community are united and Russia is becoming a global pariah.”
Russian opposition leader Navalny speaks out from prison
Prominent Russian opposition leader Alexei Navalny has spoken out against the partial mobilisation from prison, where he is being held on a number of charges described as bogus by international human rights organisations.
Speaking during the court hearing via video link, Navalny said "It is already clear that the criminal war that is going on, it is getting worse, deepening, and Putin is trying to involve as many people as possible in all this.
"He wants to smear hundreds of thousands of people in this blood."
"Sign of weakness and failure" says US ambassador as China urges a ceasefire
The United States ambassador to Ukraine has described President Putin's announcement of partial mobilisation as a sign of "weakness and failure."
"The United States will never recognize Russia's claim to purportedly annexed Ukrainian territory, and we will continue to stand with Ukraine for as long as it takes," wrote Bridget Brink on Twitter.
China, meanwhile, urged all parties to come together to discuss their security concerns.
The country's foreign ministry spokesperson described China's position as "consistent and clear" at a regular media briefing.
EU condemns Putin's 'reckless' nuclear threat
European Commission spokesman Peter Stano described Vladimir Putin's assumed reference to Russia's nuclear capability as a "reckless gamble" and called for the international community to stand up to threats.
"Putin is doing a nuclear gamble. He's using the nuclear element as part of his arsenal of terror, it's unacceptable," said Stano.
At the end of his speech this morning the Russian President made reference to his countries "various weapons of mass destruction." In March he placed his nuclear forces on a state of high alert.
"Madness" to consider weapons of mass destruction, says Pope Francis
The Pope has said it is "madness" for a country to consider using weapons of mass destruction in the Ukrainian conflict.
Pope Francis made the comments when discussing his recent visit to Kazakhstan, which gave up it's nuclear weapons in 1991.
"This was courageous," he said. "At a time in this tragic war where some are thinking of nuclear weapons - which is madness - this country said 'no' to nuclear weapons from the start."
Despite not naming Putin, the Pope described Ukrainians as being subject to savageness, monstrosities and torture, calling them a "noble" people being martyred.
Foreign Secretary condemns "blatant sham" referenda
The Foreign Secretary, James Cleverly, has condemned plans for referenda in parts of occupied Ukraine as a "blatant sham designed to seize Ukrainian land.""We will never recognise the results of any sham referendums or attempts to annex Ukraine’s sovereign territory," he said.