UPDATE 3-U.S. officials unsure whether chemical weapons used in Syria
* Reports of use in north and in Damascus suburbs
* Obama warns of "red line" and consequences, but no details
* Rep. Rogers says "high probability" chemical weapons used (Updates with Representative Rogers interview)
WASHINGTON, March 20 (Reuters) - The U.S. ambassador to Syria said on Wednesday there is no evidence so far to back reports that chemical weapons were used in Syria on Tuesday, but the United States has a large team investigating the issue.
"So far, we have no evidence to substantiate the reports that chemical weapons were used yesterday. But I want to underline that we are looking very carefully at these reports," Robert Ford, who was recalled from Damascus in February 2012, told a hearing of the House of Representatives Foreign Affairs Committee.
Meanwhile, House Intelligence Committee Chairman Mike Rogers told Reuters in an interview that there was a "high probability" that Syrian President Bashar al-Assad's forces used chemical weapons.
If President Barack Obama's administration does not reach that same conclusion by next week it would be "troublesome," the Michigan Republican said, adding that his analysis was based on public and classified reports.
Another U.S. official said that Rogers and other top lawmakers on intelligence committees had been briefed by intelligence officials this week about whether chemical weapons were used in Syria. Rogers would not confirm that.
Assad's government and rebels accused each other of launching a deadly chemical attack near the northern city of Aleppo on Tuesday. Both sides demanded international investigations. [
If confirmed, it would be the first use of such weapons in the two-year-old conflict.
Separately, U.S. and European officials told Reuters there was no confirmation that either side had used chemical weapons.
"We can't corroborate the CW claims at this point," one U.S. official said, speaking on condition of anonymity.
A U.S. intelligence official told Reuters that "no conclusive assessment has been made."
CONCERN OVER ARMS FLOW TO SYRIA
At the hearing, lawmakers expressed concern about growing Iranian military support for Assad's government, and they pressed Ford on how the United States is pushing Baghdad over Iranian weapons pouring into Syria through Iraq.
"We have had very direct conversations with the Iraqis," Ford said, listing meetings in Washington and the Iraqi capital. "We have been very direct with them about the importance of not allowing Iran to exploit the crisis in Syria, and how that is not helpful to Iraqi interests, as well as the region's interests."
Ford also said repeatedly in response to lawmakers' questions that the U.S. policy is not to provide military aid to the rebels.
The White House and the State Department on Tuesday expressed deep skepticism over the Syrian government's claims regarding the rebels using chemical weapons.
"We view this issue with extreme seriousness," Ford told the congressional hearing. "Right now we are trying to verify the reports we have seen recently about the use. There are reports about them being used both in the north and in the Damascus suburbs, the eastern suburbs of Damascus," he said.
Obama has warned that any use of chemical weapons would be a "red line" that would trigger consequences, without spelling out what those would be. Obama repeated that warning on Wednesday during a visit to Israel.
Rogers said it was the president's drawing of that red line that was likely making the administration more cautious about whether chemical weapons had been used in Syria.
"Their awkwardness here is the fact that the president has drawn a very bright red line," he said. "The problem is, though, we've communicated to our allies and our adversaries there what our red line was in this particular case.
"So if they (the Obama administration) want to take a day or two to do further review and look for physical forensic evidence and all of the things that one would do in a case like this, that's OK. But if this goes into a week from now and they're saying the same thing, that could be troublesome," Rogers said.