WASHINGTON, April 13: In an escalating confrontation, the United States accused Syria on Sunday of possessing chemical weapons, charged that its nationals had engaged US troops in combat in Baghdad and warned it against allowing senior Iraqi leaders to escape through its territory.

President George Bush stopped short of threatening US action against Damascus, but his comments were clearly intended as a warning Syria to halt support for the deposed Iraqi regime and its leaders.

“The Syrian government needs to cooperate with the United States and our coalition partners. It must not harbour any Baathists, any military officials who need to be held to account for their tenure” in Iraq, Bush told reporters at the White House.

Many Syrian nationals were killed in fighting overnight in the Iraqi capital and others have been taken prisoner, said US Defence Secretary Donald Rumsfeld, who said Syrians had entered Iraq by the busload.

Rumsfeld also reiterated charges that senior Iraqis have escaped to Syria, and that some have stayed there while others have moved on to other countries. “We believe there are chemical weapons in Syria,” Bush said without elaborating.

US intelligence has previously reported that Syria possesses stockpiles of the nerve gas sarin and is believed to have an acive bilogival programme.

Mr Rumsfeld said earlier that the United States had reports that some of Iraq’s weapons of mass destruction may have been sent to a neighbouring country, but would not identify the country.

“Each situation will require a different response,” Mr Bush said. “First things first. We’re here in Iraq now.”

In an interview with the BBC, Secretary of State Colin Powell warned Damascus it would be “very unwise if, suddenly, Syria becomes a haven for all these people who should be brought to justice, who are trying to get out of Baghdad.”

“The government’s making a lot of bad mistakes, a lot of bad judgment calls, in my view, and they’re associating with the wrong people,” Rumsfeld said in a interview here with CBS television.

Syrian officials emphatically denied that it was harbouring members of the regime or had weapons of mass destruction, and said Washington was seeking to divert attention from the chaos and lawlessness that has followed the collapse of the Iraqi regime.

“We will not only accept the most rigid inspection regime, we will welcome it heartily,” said Imad Moustapha, the number two in the Syrian embassy in the United States.

Mr Rumsfeld declined to comment on a report in the Washington Times that two top Iraqi scientists involved in its weapons of mass destruction programme had taken refuge in Syria.

Asked what if President Saddam Hussein turned up alive in Syria, Rumsfeld said, “Then I think Syria would have made an even bigger mistake.”

Saddam heads a US list of more than 50 Iraqis wanted by coalition forces.

Targeted in at least two “decapitation” air strikes during the 23-day-old war, his fate remains a mystery.

US Army General Tommy Franks, the commander of the coalition forces, said US forces have samples of Saddam’s DNA.

He said he believed it would be possible to identify Saddam, “unless remains were removed” at the site of recent heavy bombings in a residential area where Saddam was believed to be meeting with his top intelligence officials.

“The appropriate people with the appropriate forensics are doing the appropriate checks,” Franks said in an interview with CNN. Rumsfeld said that if the Iraqi leader is alive, he might try to escape the country.

“He’s done it once before,” he said in an interview with NBC. “He got out of the country years and years ago, after an attempted coup, and went to Egypt, as I recall.”

Bringing in Iraqi leaders and scientists has become a top priority for US forces as they turn their attention from combat to uncovering Iraq’s hidden weapons of mass destruction programmes.—AFP