Syrian rebels have recently received new weapons that could "change the course of the battle" against the Syrian regime, a spokesman for the Free Syrian Army told AFP on Friday.
The "Friends of Syria" group of countries that support the rebels is expected to announce in Doha on Saturday that it will arm the opposition, FSA media and political coordinator spokesman Louay Muqdad said.
"We've received quantities of new types of weapons, including some that we asked for and that we believe will change the course of the battle on the ground.
"We have begun distributing them on the front lines, they will be in the hands of professional officers and FSA fighters," he said.
He did not specify what weapons had been received or when they had arrived, but added that a new shipment was expected in the coming days and recalled that the rebels had asked for "deterrent weapons".
"That means anti-aircraft weapons, anti-tank weapons, as well as ammunition," he said.
Senior opposition figure Burhan Ghalioun confirmed that the FSA had recently received "sophisticated weapons" including "an anti-aircraft defence system".
Another opposition source, speaking on condition of anonymity, said the system was "Russian-made" but declined to say which country had supplied it.
The apparent influx of arms comes after the United States said it would provide rebel forces with "military support", although it has declined to outline what that might entail.
"The weapons will be used for one objective, which is to fight the regime of (President) Bashar al-Assad," Muqdad insisted.
"They will be collected after the fall of the regime, we have made this committment to the friends and brotherly countries" that supplied the arms, he said.
On Thursday, Muqdad said rebels needed short-range ground-to-air missiles, surface-to-air missiles known as MANPADs, anti-tank missiles, mortars and ammunition.
Saturday's Friends of Syria talks in Qatar will be attended by ministers from Britain, Egypt, France, Germany, Italy, Jordan, Qatar, Saudi Arabia, Turkey, the United Arab Emirates and the United States.
They are expected to discuss military help and other aid for rebels after an onslaught by government forces who have retaken key areas.
"We are optimistic because the international community has finally decided to protect the Syrian people and Syrian civilians and arm the FSA," Muqdad said.
He added that rebels were expecting "a clear and official announcement by the countries participating (in Doha) on the arming of the FSA".
"That's what we are hoping for, that's what we are waiting for," he added, declining to say which countries were providing new weaponry.
"We received information that in the coming days, we will receive new shipments of weapons that will change the course of the battle and the equation of death imposed by Bashar al-Assad," he said.
Muqdad said that FSA chief of staff General Salim Idriss was not expected to attend the Doha gathering.
"For now, our presence is not required" because "all the countries are aware of the clear demands of the revolution after numerous meetings with Idriss."
Syrian rebels have frequently urged nations that back the uprising to supply them with heavy weapons to tackle the regime.
But their backers, especially in the West, have been reluctant to do so for fear that those weapons could fall into the hands of radical rebel groups such as the Al-Qaeda-allied Al-Nusra Front.