ITV News Correspondent Dan Rivers has the latest from Kharkiv - Ukraine's second largest city and a key target for Putin's troops
Ukraine's peace talks with Russia begun on Sunday afternoon, a Ukrainian official has said, as President Putin's invasion was met with fierce Ukrainian resistance over the weekend.
Anton Geraschenko, an adviser to Ukraine's Minister of Internal Affairs, told ITV News that the two sides started discussions on Sunday at around 3.30pm.
Ukraine president’s office said earlier that Ukrainian envoys will meet with Russian diplomats to discuss the crisis. The statement added that the two sides would meet on the border between Ukraine and Belarus.
The talks come as a top EU official announced a new package of sanctions to "step up support for Ukraine". The 27-nation bloc will close its airspace to Russian airlines, fund arms supplies to Ukraine and ban pro-Kremlin media. Additionally, buy weapons for Ukraine.
Ukraine claims it has "complete control" over Kharkiv after Russian troops marched on the country's second largest city earlier on Sunday. However, the wider picture remains unclear.
Early on Sunday, video from Kharkiv showed fighting in the streets as Russian troops approached the city, which is located about 20 kilometres south of the border with Russia.
They had initially remained on its outskirts without trying to enter the city, but Ukrainian authorities said opposition forces moved in on Sunday morning.
Russia’s Defence Ministry initially claimed more than 470 Ukrainian troops had surrendered near the city, but later in the day Kharkiv's governor claimed "control is completely ours".
However, ITV News Correspondent Dan Rivers, posted in Kharkiv, said on Sunday evening: "We’ve been hearing sirens echoing across the city and the odd crump of shells - clearly there is some fighting going on in the centre of the city."
How were the talks negotiated?
Earlier on Sunday, Ukraine’s president said his country was ready for peace talks with Russia, but not in Belarus - describing the country as a staging ground for Putin's invasion.
Speaking in a video message, President Volodymyr Zelenskyy named Warsaw, Bratislava, Istanbul, Budapest or Baku as alternative venues.
The Kremlin had already announced a Russian delegation had arrived in the Belarusian city of Homel for talks with Ukrainian officials.
It's not clear how the location was eventually agreed, but President Zelenskyy's office announced on Sunday afternoon that the two sides would meet on the border between Ukraine and Belarus.
Where are Russian troops in Ukraine and which areas have been targeted?
Russia's invasion of Ukraine continued over the weekend as attacking forces unleashed a wave of attacks targeting airfields and fuel facilities.
Earlier on Sunday, Kyiv was eerily quiet after huge explosions lit up the morning sky and authorities reported blasts at one of the airports. A main boulevard was practically deserted as a strict 39-hour curfew kept people off the streets. Authorities warned that anyone venturing out without a pass would be considered a Russian saboteur.
ITV News Global Security Editor, Rohit Kachroo, was in the capital overnight. He described "another dark night of heavy shelling and loud explosions" as red smoke billowed into the air.
President Zelenskyy’s office said Russian forces blew up a gas pipeline in Kharkiv, prompting the government to warn people to protect themselves from the smoke by covering their windows with damp cloth or gauze.
“We will fight for as long as needed to liberate our country,” Zelenskyy vowed.
“The past night was tough – more shelling, more bombing of residential areas and civilian infrastructure," he added.
"There is not a single facility in the country that the occupiers wouldn’t consider as admissible targets.”
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What about the refugees fleeing Ukraine?
More than 360,000 Ukrainians have fled to Poland, Moldova and other neighboring countries, and the United Nations warned the number could grow to 4 million if fighting escalates.
ITV News Correspondent Lucy Watson was at a train station in Poland on Sunday and has heard some of the harrowing stories from Ukrainians who have fled across the border.
She said people there are focused on the basics - "can I keep my child warm tonight? Where are we going to sleep tonight? They don't want pity, they want help".
It comes as the UK government faced growing criticism for not acting quickly enough to help Ukrainian refugees.
Government ministers say they’re sending humanitarian aid to Ukraine’s neighbours to help deal with the rising numbers of refugees.
For refugees to gain entry to the UK, however, certain criteria must be met as part of the immigration system here.
What sanctions are in place against Russia?
The President of the EU Commission announced a new set of sanctions on Russia on Sunday.
Ursula von der Leyen said EU airspace will be closed to Russian-owned, Russian registered or Russian-controlled aircraft. She also announced new restrictions on Russian media, with Russia Today and Sputnik banned in the EU.
Thirdly, a set of sanctions on Belarus will be implemented, which she described as "the other aggressor" in the war. The EU has also committed to funding the purchase and delivery of weapons and other equipment to Ukraine.
“For the first time ever, the European Union will finance the purchase and delivery of weapons and other equipment to a country that is under attack,” said European Commission president Ursula von der Leyen. The EU will also ban some pro-Kremlin media outlets, she said. The US also stepped up the flow of weapons to Ukraine, announcing it will send Stinger missiles, for shooting down helicopters and other aircraft, as part of a package approved by the White House on Friday. Germany likewise plans to send 500 Stingers and other military supplies.
The UK, European Union and United States have agreed to block “selected” Russian banks from the SWIFT global financial messaging system.
What is Swift and why does it matter some Russian banks have been banned from it? ITV News Political Editor Robert Peston explains
The system moves money around more than 11,000 banks and other financial institutions worldwide, part of a new round of sanctions aiming to impose a severe cost on Moscow for the invasion.
They also agreed to impose ”restrictive measures” on Russia's central bank.
Although there are not currently any NATO troops on the ground, allies of Ukraine have been sending weapons, supplies and aid to the country.
How has Russia reacted to sanctions?
President Vladimir Putin has ordered Russian nuclear deterrent forces be put on high alert, as tensions with the West mount over his invasion of Ukraine.
Speaking at a meeting with his top officials, the Russian president claimed leading NATO powers had made “aggressive statements” as well as imposing hard-hitting financial sanctions against Russia and leading officials.
Putin ordered the Russian defense minister and the chief of the military’s General Staff to put the nuclear deterrent forces in a “special regime of combat duty.”