Britain and the US are considering stepping up support to the Syrian rebels with the provision of non-lethal military equipment and strategic military training.
Prime Minister David Cameron discussed the plan with US Secretary of State John Kerry during a meeting in London and the two governments are holding talks with other European partners.
A decision is expected to be taken tomorrow in Rome at the end of an international conference, attended by representatives of the Syrian National Coalition, on the conflict which has already killed more than 70,000 people.
"We are determined that the Syrian opposition is not going to be dangling in the wind wondering where the support is or if it is coming, and we are determined to change the calculation on the ground for President [Bashar al-Assad]," Kerry told reporters after meeting British Prime Minister David Cameron and Foreign Secretary William Hague in London.
European officials, speaking on condition of anonymity, told the Washington Post that Britain, France, Germany and Italy favour a policy shift towards supplying carefully vetted rebel groups with "things that don't of themselves kill people," such as night-vision equipment communication devices, body armour, flak jackets and military vehicles.
"In the face of such murder and threat of instability, our policy cannot stay static as the weeks go by," Hague said.
"We must significantly increase support for the Syrian opposition. We are preparing to do just that."
Western powers have been long criticised for not taking effective measures to aid the uprising against Assad and put an end to the two-year conflict.
The West resilience to directly arming the rebellion has been partially motivated by the presence of some jihadists among the various rebel factions.
The Islamist al-Nusra Front, which has played a prominent role in the rebellion against Bashar al-Assad's regime, was designated as a terrorist organisation by the Obama administration in December.
"Not everybody who's participating on the ground in fighting Assad is people who we are comfortable with," Obama then told ABC.
"There are some who, I think, have adopted an extremist agenda, an anti-US agenda, and we are going to make clear to distinguish between those elements."