Syria's chemical weapons could be used at "a moment's notice" and the international community should not accept any assurances from Syrian officials that they will not be used, US House Intelligence Committee Chairman Mike Rogers said on Wednesday.
US and other Western officials recently issued sharp warnings to Syrian President Bashar Assad not to deploy chemical weapons. Syria called those warnings a "pretext for intervention" in the civil war.
Rogers, a Republican, told Reuters in an interview that the Syrian government's activities related to chemical weapons were a shift in posture and a major concern.
"I believe that they have put elements of their chemical weapons program in a condition of which they could be used at a moment's notice, which is very different from before," Rogers said.
"And some notion that they have promised not to use them, I don't think the international community...should take that on face value," he said.
"This is a regime that's getting more desperate by the day. They have affirmatively put elements of their chemical weapon program in a position for use, that is something that we should all be concerned about."
His comments came amid reports that Assad's forces had fired Soviet-era Scud ballistic missiles against rebels in a significant escalation of the nearly two-year-old conflict that has already killed more than 40,000 civilians.
The alleged use of Scud-style weapons and the changed posture on chemical weapons suggests desperation on the part of Assad's government, Rogers said.
He added that "It would not be unusual for a regime that possesses some fairly sophisticated weapons systems in these last, I argue days and months, or days and weeks, of a pretty desperate regime to use the weapons at its disposal.
"So Scuds, and I make the next leap of chemical weapons, I think is of real concern."
"Friends of Syria" group meets in Morocco to discuss uprising
On Wednesday, Western and Arab nations sympathetic to Syria's uprising against Assad gave full political recognition to the opposition, reflecting a hardening consensus that the 20-month-old uprising might be nearing a tipping point.
Meeting in the Moroccan city of Marrakech as rebels battled Assad's troops on the outskirts of his Damascus power base - and shortly before the capital was rocked by a huge explosion - the "Friends of Syria" group called on Assad to step aside.
But tensions between the United States and the Syrian opposition coalition surfaced at the same meeting when its leader criticized Washington's designation of the Islamist Jabhat al-Nusra rebel brigade as a terrorist organization.
Hours earlier, US President Barack Obama announced Washington would recognize the coalition of opposition groups, led by Sunni Muslim cleric Mouaz Alkhatib, as Syria's legitimate representative, joining France, Britain, Turkey and Gulf states.
"Participants acknowledge the National Coalition as the legitimate representative of the Syrian people and the umbrella organization under which the Syrian opposition are gathering," said the Marrakech declaration after a meeting attended by 130 ministers and officials.
The gathering brought together Western and Arab nations opposed to Assad, whose family has ruled Syria for 42 years. But it excluded Russia, China and Iran, which have backed Assad or blocked efforts to tighten international pressure on him.
"Bashar Assad has lost legitimacy and should stand aside to allow a sustainable political transition," said the text.
Referring to Western reports suggesting Assad might use chemical and biological weapons, the text said "any use of chemical weapons in Syria would be abhorrent and that this would draw a serious response from the international community".
Qatar reinforced that message after the meeting, urging Assad to take
the "brave decision" to step down, while Britain called on him to end a
war it said he could not win.
Participants announced the creation of a relief fund "to support the Syrian people", calling on states and organizations to make contributions to the fund.
Western officials are due to meet commanders of a newly formed rebel military command in Turkey next week.
Syria's state news agency SANA said Obama's recognition of the political opposition, which coincided with Washington's designation of the radical Islamist Jabhat al-Nusra group, part of the rebel force against Assad, as a terrorist organization "proves American hypocrisy".
Opposition calls on US to reconsider terrorist group designation
Coalition leader Alkhatib urged the United States to reconsider its decision to designate the militant Islamist Jabhat al-Nusra as a terrorist group.
"The decision to consider a party that is fighting the regime as a terrorist party needs to be reviewed," he said.
"We might disagree with some parties and their ideas and their political and ideological vision. But we affirm that all the guns of the rebels are aimed at overthrowing the tyrannical criminal regime."
Alkhatib called on Syria's Alawite minority to launch a campaign of civil disobedience against Assad, an Alawite facing a mainly Sunni Muslim uprising against his rule.
Fighting is moving closer to Assad's residence in the center of Damascus, and early on Wednesday government forces fired artillery and rockets at southwestern suburbs of the capital adjacent to the Mezzeh military airport, activists said.
State television reported an explosion at the gate of the Interior Ministry in Damascus. The ministry is in Kafar Souseh, an area contested by rebels and forces loyal to Assad. A resident reported sirens and shooting after a "huge explosion."
SANA said on Wednesday that "terrorists" detonated two bombs in the Damascus district of Jaramana, killing one person and wounding five, and another two bombs behind the Justice Ministry in Damascus, wounding one person.
In central Syria, an attack on a village killed or injured as many as 200 members of Assad's Alawite minority sect, activists said, but it was unclear who was behind the assault.
The rebels now hold a near continuous arc of territory from the east to the southwest of the capital. With conditions deteriorating, Damascus residents face power and food crises.