Washington: The Obama administration has returned to the idea of arming moderate Syrian rebels, current and former officials said, because many officials see it as one of the few steps available to shore up the opposition without drawing the military into the two-year-old civil war.

Advocates see delivering weapons as the least invasive of the alternatives available to President Barack Obama. One former official called it the “best of the bad options”.

Obama is facing pressure to make good on his vow to take stronger action if he finds Syrian President Bashar Al Assad’s regime has used chemical weapons. The White House says US intelligence agencies have evidence that the Al Assad regime has used chemical weapons, but Obama has said more evidence was needed.

For a president who wants to stay out of the Syrian war, providing weaponry is the least risky way for the US to punish Al Assad without committing to use direct force, if Washington is convinced that he crossed the chemical weapons red line, current and former officials said.

A senior Obama administration official said the option of arming the rebels is now being actively considered, though a decision has yet to be made and arms transfers aren’t imminent.

The option, the official added, is both “the least of the slippery slope but also a reasonable next step on this trajectory of strengthening the opposition.”

Other options for Washington pose a heightened risk of pulling the US into the war, including establishing a no-fly zone that would require US forces to take out Syrian antiaircraft batteries.

On Tuesday, President Obama said the international community must be convinced of the regime’s use of chemical weapons, suggesting broad consensus was necessary to support military intervention. Officials said there is little appetite in the US or the North Atlantic Treaty Organisation for going down that route.

If the US provides arms, it could do so alongside the UK and France, which plan to start supplying arms as early as this summer. Gulf states are already providing weapons to different factions of the opposition.

Last year, a roster of high-level administration officials backed a Central Intelligence Agency proposal to arm the rebels.

But Obama overruled them, rejecting the idea of introducing more arms into the conflict. Opponents of arming the rebels said that providing US arms wouldn’t help speed the fall of Al Assad and could inadvertently strengthen Islamists should they get hold of the weapons.

In recent weeks, some administration officials who once favoured arming rebels - including Director of National Intelligence James Clapper and the chairman of the Joint Chiefs of Staff, General Martin Dempsey - have reconsidered because of the influence of Islamist groups in rebel ranks has grown.

But US officials say the US has had more opportunities to evaluate potential rebel partners, providing moderate rebels with nonlethal assistance, including food and medicine.

The senior Obama administration official said the US experience with nonlethal aid has been instructive. “We can see how it can be done and we know who we’re dealing with,” the official said.

“We are engaging with the opposition. We are getting to know the opposition better,” White House press secretary Jay Carney said on Wednesday, suggesting the US may be better able to distinguish credible opposition fighters from extremists.

The war in Syria is a worsening dilemma for the president. Another Middle Eastern conflict would undermine Obama’s ambitious domestic agenda and his call for a more robust “nation-building” project at home.

Polls show a majority of Americans don’t believe the US has a responsibility to wade into the Syrian conflict.

Yet, Obama said at a news conference Tuesday that he won’t ignore a humanitarian disaster in Syria, where 70,000 have died, according to United Nations’ estimates.