Al-Jaafari said on Thursday in Washington Iran should not interfere in Iraq's internal affairs, and said Baghdad's relations with the US would remain strong even if Washington confronted Tehran militarily over its nuclear ambitions, officials who attended the meeting said.
The Syrian government invited al-Jaafari earlier this week to visit Damascus for high-level talks, said the Iraqi leader, who will meet US President George Bush at the White House on Friday.
Al-Jaafari told the lawmakers he had agreed to the visit and an announcement would be made soon, according to the sources.
"He said that that meeting must be productive, must produce results" on issues including border security, one source said.
Pressure on Syria
House International Relations Committee chairman Henry Hyde, an Illinois Republican, was among members of Congress who attended.
Al-Jaafari said international pressure helped force Syria to withdraw its troops from Lebanon, and he believed a similar campaign on behalf of Iraq could prompt Damascus to improve cross-border security, the officials said.
Syria has been accused of letting
fighters infiltrate Iraq
Earlier on Thursday, al-Jaafari met Vice-President Dick Cheney and National Security Adviser Stephen Hadley.
US administration officials declined to comment on those talks.
Asked about the possibility of a conflict with Iran, the Iraqi leader told lawmakers that relations with the US "will not change even if the United States is in crisis with one of our neighbours", according to a source who attended the meeting.
Two other sources confirmed that account.
Washington accuses Syria of doing too little to prevent fighters from crossing into Iraq, where they fight US forces.
Syria, which opposed the US-led war in Iraq, says it is cooperating.
US officials accused Syria on Thursday of keeping intelligence agents in Lebanon in defiance of the UN.