Rebel fighters launch a rocket towards forces loyal to Syria's President Bashar al-Assad in Deir al-Zor. Photo: Reuters
Beirut: Groups affiliated with al-Qaeda are redeploying their resources in rebel-held parts of Syria amid widespread fears that any strikes carried out by the US would target not only the Syrian government but also Islamists in the opposition, rebels say.
In many parts of the northern and eastern provinces that have fallen almost entirely under rebel control, extremist groups have been evacuating headquarters, moving military equipment and, in some instances, fleeing to what is considered safer ground in mountainous terrain.
The moves mirror preparations by forces loyal to President Bashar al-Assad, which are in the process of shifting troops and armour out of major military facilities and into schools and residential neighbourhoods, witnesses and residents say.
The Obama administration has stressed that a decision to attack Syria has not yet been made, amid efforts to calibrate a response to last week's suspected chemical weapons attack.
The US has also given no indication that any of the extremist groups in the Syrian opposition would be on its list of targets, even though two key groups are designated terrorist organisations: Jabhat al-Nusra and the Islamic State of Iraq and the Levant, which has expanded into Syria from Iraq.
But the threats of action against Mr Assad have already sown widespread panic along many fronts within the bitterly divided country, in just one indication of the profound complexity of the conflict in which the US has long resisted entanglement.
''Why did they wait until the Islamists are in control to make this strike?'' asked Saleh al-Idlibi, a spokesman in Idlib province for the Liwaa al-Umma Brigade, an Islamist group that has not been designated a terrorist organisation by the US but supports those that are. ''This is why the jihadi groups are afraid.''
In a statement disseminated on the Twitter account of one of its supporters, the group Fateh al-Islam offered advice to Islamists, warning that for every US missile that hits a regime target, another will strike a jihadi base.
''Start changing your locations, and use safe houses, and don't move around in obvious convoys,'' said the supporter, Abdullah Saker, detailing precautionary measures. ''Take away mobile phones from the troops, and send them away from the leadership.
''America destroyed jihadi bases in a very short period of time in Afghanistan and Iraq, and killed a large number of them, because they weren't prepared. So don't fall in the trap of laziness,'' he added.
Even among rebels who have longed for Western help in their fight against Mr Assad, there is widespread confusion over the prospect that the US might finally intervene.
The Free Syrian Army, which claims to represent a majority of the rebel units fighting in Syria, welcomed the Obama administration's threats of retaliation for the alleged chemical attack.
Syrians would prefer to overthrow Mr Assad without foreign help, but if the West does carry out strikes, the Free Syrian Army intends to take advantage of any disarray in the ranks of regime forces to advance its own positions, said Louay al-Mokdad, political and media co-ordinator for the FSA.
''We are going, for sure, to make the most of this operation to increase our situation on the ground, to try and control and liberate more areas,'' he said. ''This is our right. Our fighters on the ground should use anything, even a change in the weather if it will help them.''
However, those who support intervention expressed concerns about how the strikes would unfold.
''People here are very worried the strikes will be intended to help the regime,'' said Abu Hamza, an activist in the Damascus suburb of Darayya, where the war has left a town of nearly 500,000 a ravaged, emptied ruin.