Under fire from Britain and the United States, with its old foe Israeli jumping on the bandwaggon, Syria strongly denied allegations that it was aiding the remnants of Saddam Hussein's Iraqi regime or developing its own weapons of mass destruction.

The stand-off between Washington and Damascus brought calls for restraint on the part of the United States from France, Germany and Russia, the main opponents of the US-led war on Iraq.

Powell insisted Damascus turn away fleeing supporters of Saddam Hussein as the White House branded Syria "a terrorist state" and "a rogue nation".

"We will examine possible measures of a diplomatic, economic or other nature as we move forward," Powell warned.

But Syrian President Bashar al-Assad had already promised that his country would stop fleeing Iraqis crossing the border, British Prime Minister Tony Blair said.

Blair told parliament that Britain and the United States had no plans to invade Syria, despite US charges that senior Iraqi regime figures are taking refuge there.

"I spoke with President Bashar al-Assad over the weekend and he assured me that they would interdict anybody who's crossing over the border from Iraq into Syria," Blair said. "I believe they are doing that."

Blair also said there were "no plans whatever to invade Syria."

A top Israeli official warned Damascus not to "play with fire" after Syrian Foreign Minister Faruq al-Shara made a strong anti-Israeli statement amid strains between Washington and Damascus.

"Israel is not looking for an escalation with Syria, but Damascus is playing with fire by threatening us with its terror arsenal," a senior official close to Prime Minister Ariel Sharon told AFP.

"We warned Syria against the temptation to attack us during the war in Iraq. That would be an even greater mistake for them after the victory of the coalition."

The official said that Israel, which seized the Golan Heights from Syria in the 1967 Arab-Israeli war, was for now restricting itself to "supporting US efforts to stop Syrian support for terrorism."

Israeli Defence Minister Shaul Mofaz also said the Jewish state would brook no threat from Damascus.

"We must monitor what it happening there. The Americans have taken out a 'yellow card' on them, and were right to do so," he said on army radio, using the soccer term for a serious warning.

Syria is already subject to some US sanctions as it is designated a "state sponsor of terrorism" by the State Department.

On Sunday, US President George W. Bush charged Syria had chemical weapons and renewed the allegation that Syria has taken in remnants of Saddam's dismantled regime and his Baath party. Britain and Israel have made similar allegations.

Syrian foreign ministry spokeswoman Bussaina Shabban dismissed the US claims as groundless.

"Many of these allegations addressed to Syria are absolutely groundless," she told BBC television by telephone from Damascus.

"I think they are just being initiated and promoted by people who are intent on spoiling US-Syrian relations and British-Syrian relations, but I don't think they will succeed," she added.

Powell noted that Syria had pledged last week to close its border with Iraq to all non-humanitarian traffic but stressed that the border was porous and warned Damascus specifically against allowing any one of the 55 senior Iraqi official wanted by US forces to cross.

"These are the kinds of individuals who should not be allowed to find safe haven in Syria," he said, adding that if any of them had crossed the border, they should be detained.

"Once they get into Syria and start heading to Damascus, I would expect Syrian authorities would do everything they could not to provide these people safe haven," Powell said.

Powell did not say what sanctions would be considered but officials said Washington could recall its ambassador to Damascusas it did in 1986 after evidence surfaced of direct Syrian involvement in an attempt to blow up an Israeli plane.

The US military also claimed that most of the foreigners who travelled to Iraq to fight against invading US-led forces there were from Syria.

"We're seeing them in the greatest density," Brigadier General Vincent Brooks told reporters when asked why he kept mentioning Syria when he spoke of foreign fighters in Iraq.

"Whether it's something done by governments we don't know," he said at US Central Command forward headquarters, adding that he had no idea of the numbers of such volunteers.

SPACE.WIRE