Cooperation between the Western-backed Free Syrian Army (FSA) and al-Qaida's Syrian affiliate, Jabhat al-Nusra, continues even as the FSA tries to obtain more American arms.

The Wall Street Journal reports that the Syrian Revolutionaries Front, an FSA element, has teamed up with Jabhat al-Nusra in recent weeks in attempts to capture strategic hilltops in Syria's southwestern Quneitra province overlooking the Israel-held Golan Heights.

"The FSA and Nusra Front are cooperating on the front line," Abu Omar Golani, the Syrian Revolutionaries Front's media coordinator, told the Journal.

FSA forces have struggled over the past year to seize the hills in the area from government forces. Cooperation between the FSA and Jabhat al-Nusra has included "military operations rooms" where they jointly planned strategy before battles and helped coordinate unit activities, according to Golani.

FSA leaders denied that such coordination was taking place even though Jamal Maarouf, head of the Syrian Revolutionaries Front, has previously admitted to fighting alongside Jabhat al-Nusra.

"It's clear that I'm not fighting against al-Qaida. This is a problem outside of Syria's border, so it's not our problem. I don't have a problem with anyone who fights against the regime inside Syria," Maarouf told the U.K.'s Independent newspaper last month.

Maarouf also expressed his support for Jabhat al-Nusra in a January Twitter post, saying all of the anti-Assad forces – including the al-Qaida affiliate – were fighting together against the regime.

The news comes as Ahmed Jarba, president of the rebel Syrian National Coalition (SNC), is in Washington this week and is slated to meet with President Obama and Secretary of State John Kerry.

Jarba publicly appealed to the Obama administration to provide the FSA with more advanced weapons, especially shoulder-launched anti-aircraft missiles such as the Stinger. He vowed that advanced weapons systems would only be used by select "professional" fighters to ensure that they do not fall into the hands of Islamic extremists.

Videos surfaced in the Internet over the past month showing FSA fighters using U.S.-made TOW anti-tank missiles. Rumors in the Israeli press suggest that the CIA has moved weapons to Jordan and plans to start arming small groups of "vetted" Syrian rebels within a month.

Fears that such weapons could fall into Jabhat al-Nusra's hands have spurred reluctance on Capitol Hill to arm the FSA rebels, who have experienced a recent spate of defections.

Numerous FSA Supreme Military Council officials have expressed support for Jabhat al-Nusra, or had their brigades fight alongside the al-Qaida franchise, since Syria's civil war started in 2011.

Such developments may serve to further reinforce reluctance in Washington to arm the FSA.