President Donald Trump has declared that a “reign of terror is over” as he marked the death of an Iranian general killed in a US strike and as the Pentagon scrambled to reinforce the US military presence in the Middle East in preparation for reprisals.
General Qassem Soleimani “made the death of innocent people his sick passion”, Mr Trump said from his estate in Palm Beach, Florida, adding “a lot of lives would have been saved” if he had been hunted down years ago.
Mr Trump said the Iranian general was plotting “imminent and sinister attacks” and added: “We caught him in the act and terminated him.”
The US president said: “We took action last night to stop a war.
“We did not take action to start a war.”
Mr Trump said the US was not seeking regime change in Iran, but claimed the world was a safer place without “monsters” such as Gen Soleimani.
He said: “If Americans anywhere are threatened we have all of those targets fully identified and I am ready and prepared to take whatever action is necessary, and that particularly refers to Iran.”
British nationals are being warned against all travel to large swathes of Iraq amid the ratcheting of tensions.
The Foreign Office was also advising against all but essential travel to Iran and for those in the region to "remain vigilant".
Foreign Secretary Dominic Raab said the updated advice was issued due to "heightened tensions in the region" and would be kept under review.
"The first job of any government is to keep British people safe," he added.
Meanwhile, thousands of mourners gathered on Saturday for a funeral procession through Baghdad for Iran's top general and other militants killed in the airstrike.
Many of the mourners were dressed in black, and they carried Iraqi flags and the flags of Iran-backed militias that are fiercely loyal to Soleimani.
ITV News Washington Correspondent Robert Moore examines why Trump ordered the killing
The procession began at the Imam Kadhim shrine in Baghdad, one of the most revered sites in Shiite Islam. Mourners marched in the streets alongside militia vehicles in a solemn procession.
The mourners, many of them in tears, chanted: "No, No, America," and "Death to America, death to Israel".
Mohammed Fadl, a mourner dressed in black, said the funeral is an expression of loyalty to the killed leaders.
"It is a painful strike, but it will not shake us," he said.
Two helicopters hovered over the procession, which was attended by Prime Minister Adel Abdul-Mahdi and leaders of Iran-backed militias.
The gates to Baghdad's Green Zone, which houses government offices and foreign embassies, including the U.S. Embassy, were closed.
The United States is sending nearly 3,000 more Army troops to the Mideast in the volatile aftermath of the killing ordered by Mr Trump, defence officials said.
Also Friday, the Pentagon placed an Army brigade in Italy on alert to fly into Lebanon if needed to protect the American Embassy there, part of a series of military moves to protect US interests in the Middle East.
Reinforcements were ordered as US officials said they had compelling intelligence that Gen Soleimani, the commander of Iran’s Quds Force who was killed in the US strike, was planning a significant campaign of violence against the United States.