British leaders today appeared to be walking a fine line on Syria -- echoing the Bush administration's tough warning that the country should not support political fugitives from neighboring Iraq, yet insisting that President Bashar Assad's government should be dealt with by diplomatic means.

Foreign Secretary Jack Straw said Syria must close its borders to fleeing leaders of Saddam Hussein's deposed government. But Straw, speaking for the United States' closest ally in the Iraq war, declined to label Syria a "rogue nation," a term officials in Washington used on Monday.

"Syria has an opportunity to prove that it's not in that category," Straw said at a news conference in Qatar, part of a tour he is making through the Persian Gulf region. "We look forward to them understanding this new reality and moving forward."

U.S. officials' tough talk to Syria has appalled many people in Europe, where public opinion has been overwhelmingly opposed to the Iraq war. Some people said they believe the new statements are confirmation that Iraq will be just the first in a series of countries to face U.S. attack.

The French government, which has expressed concern that the U.S. doctrine of preventive war might lead to further conflicts, has been playing down worries over Syria as part of a diplomatic effort to curb anti-U.S. rhetoric and repair relations with Washington.

At a news conference Monday, Foreign Minister Dominique de Villepin said the Syria issue needed to be resolved "with the assets we have: dialogue, consultations." It was necessary to display "restraint, moderation, [and] a constructive role in support of the search for solutions." On Monday, British Prime Minister Tony Blair told the House of Commons that he had received assurances from Assad that Syria would not harbor high-level fugitives from Iraq nor allow the transfer of Iraqi weapons of mass destruction into Syria.

Blair was peppered with questions from lawmakers who expressed fears that Syria was next on Washington's list for a preemptive military strike and that Britain would be dragged into it. Blair dismissed those concerns as just another "conspiracy theory."

"I have the advantage of talking to the American president on a regular basis, and I can assure you there are no plans to invade Syria," he said.

In tone and content, Blair's and Straw's statements differed markedly from those made by the Bush administration, which has outlined a list of concerns about not only Syria's recent conduct but also its alleged development of chemical weapons and support for militant Palestinian groups opposed to Israel. While the White House characterized Assad as an "untested leader," Straw told reporters that Syria was run by "intelligent people who have the future interest and welfare of their country at heart."

British officials say they share American concerns but have worked hard over the past few years to cultivate better diplomatic relations with Syria. Blair hosted the British-educated Assad last December on a state visit, during which the Syrian president met with Queen Elizabeth II. Britain dispatched a Foreign Office minister, Mike O'Brien, to meet Monday with Assad in the Syrian capital, Damascus.

The British are particularly concerned that accusing Syria of having chemical weapons would strike Arabs as a clear-cut example of double standards, given that neighboring Israel has a full-fledged nuclear weapons program. "I believe it would immeasurably increase the sense of Arab resentment and anger, and it wouldn't do Israel any good at all," said Alan Munro, a retired British diplomat who served in Arab countries. "This is one of those issues where Blair and Straw would have to break with Washington."

Douglas Hurd, a former British foreign secretary, called for "a period of pause and reflection." He told BBC Radio, "The moment you begin to touch Syria, you throw the whole Arab-Israeli question into the center of your considerations."

Spain, another U.S. ally in the Iraq war, also expressed opposition to an attack on Syria. "Syria is and will remain a friend of Spain and will not be the target of any military action," said Prime Minister Jose Maria Aznar.

Russia, France and the European Union also urged the United States to show restraint toward Syria. "The region is going through a very difficult process, and I think it would be better to make constructive statements to see if we can cool down the situation," Javier Solana, the EU's foreign policy representative, told reporters.

Italy, meanwhile, announced that it would send up to 3,000 soldiers to Iraq to help keep order and deliver humanitarian aid. The Italian parliament approved the dispatch of the troops, who would play no role in combat.

Correspondent Robert J. McCartney in Paris contributed to this report.

British Foreign Secretary Jack Straw, at a news conference in Qatar, says Syria must understand "new reality."