UK Foreign Secretary Jack Straw has insisted Syria is not the US and UK's next target in their campaign against weapons of mass destruction.
Jack Straw will meet US interim administrator Jay Garner in Kuwait
American rhetoric against Syria has become increasingly hostile, with President George Bush saying he believed it had chemical weapons.
Mr Straw said there were important questions for Syria to answer, arguing there was much evidence it had been cooperating with Saddam Hussein's regime.
UK Foreign Office Minister Mike O'Brien is visiting Damascus on Monday, while Mr Straw is in Kuwait for talks about rebuilding Iraq.
As well as his claims about banned weapons, President Bush again warned Syria not to shelter fleeing Iraqi officials.
Such allegations were branded groundless by senior Syrian officials on Monday.
Tony Blair said Syrian President Bashar al-Assad had told him he did not believe any Iraqi officials had crossed into his country.
Urging people not to believe conspiracy theories and newspaper speculation, the prime minister said there were "no plans whatsoever to invade Syria".
'Questions to answer'
Mr Straw took a similar line when he was asked if Syria could be a new military target.
The foreign secretary told BBC Radio 4's Today programme: "I have made it clear and I repeat that Syria is not 'next on the list'."
Mr Straw said: "Some fugitives may well have fled into Syria."
And he was unsure "whether they have been developing any kind of illegal or illegitimate chemical or biological programmes".
"There are questions that need to be answered."
But he argued: "What is important is that Syria agrees to sit down with the US and UK and actively cooperates over these questions that have been raised about their current relations with Iraq."
Military forces have struggled to maintain law and order in Basra
Mr Straw later told reporters in Kuwait there was "much evidence of considerable cooperation between the Syrian government and the Saddam regime in recent months."
The UK wanted undertakings that such links had now stopped, he said.
'Measured approach' needed
But Sir Andrew Green, British Ambassador to Syria between 1991 and 1994, said that if Syria had chemical weapons, it was as a "second strike capability" against Israel.
"They know perfectly well if they were to use such weapons first, the Israelis would use nuclear weapons and nobody is going to invite that," he told BBC News 24.
Sir Andrew said he hoped there would be a "much more measured approach" towards Syria, warning that to attack that country would be "extremely foolish".
While he did not think the Americans "have any such plans at the moment" there were some "wild people in Washington", he said.
"Clearly if we were to attack another Arab country then the entire Arab and Muslim world would see this as a campaign against them."
Sir Andrew argued that if members of the Iraqi regime had escaped into Syria, it would deny having them and "put them on to a plane to somewhere else".
Sir Andrew said he could not see Syria handing anyone over to the Americans, because "the Syrians have been totally opposed to this war".
Meanwhile, Syria's ambassador in London, Mouafak Nassar, blamed Israel for the start of the claims against his country.
Mr Nassar told BBC Radio 4's World At One: "We do not have any weapons of mass destruction.
"I will say I am wondering why they are targeting one Arab country after the other and ignoring totally the country which has serious weapons of mass destruction - nuclear, chemical biological - which is Israel."
Mr Nassar said Syria would not give shelter to any Iraqi officials.
And he defended support for the radical Islamic group Hezbollah, saying it had seats in Lebanon's parliament.
He argued that people fighting for freedom against Israeli occupation should not be called terrorists.
Mr Hoon said there were "no military plans for operations against Syria".
At a media briefing, the defence secretary said: "Our immediate concern is the risk that some of those involved in Iraq's weapons of mass destruction programmes might escape across the border into Syria, obviously boosting Syria's own efforts in those directions."
He added: "We want to maintain a dialogue with Syria, but we do want to set out our continuing concerns."
They have to ensure their own safety and security from armed gangs before they can start policing
Foreign Secretary Jack Straw
During his Kuwait visit, Mr Straw will meet the US interim administrator for Iraq, Jay Garner, before travelling to Qatar and Saudi Arabia on Tuesday.
The Israeli-Palestinian conflict is also among the issues discussed by Mr Straw and Mr O'Brien on their Gulf tours.