Al-Nusra fighter Syria
A Jabhat al-Nusra fighter talks on a walkie-talkie while carrying his weapon on the Al-Khazan front line of Khan Sheikhoun, northern Idlib province, Syria, May 17, 2014. Reuters/Hamid Khatib

The Islamic State of Iraq and Syria (ISIS), which changed its name to the Islamic State after it declared the formation of an Islamic caliphate on June 30, has taken over large swaths of land in Iraq over the past month. Now, it may have switched its focus to Syria. The group's militias advanced in eastern Syria, capturing an oil refinery last week and taking over the town of Albu Kamal-Qaim on the border of Iraq. That's territory previously occupied by Jabhat al-Nusra, an al-Qaeda-affiliated militant group in the country.

It is not clear if the leaders of the al-Nusra battalion in Albu Kamal-Qaim pledged allegiance to ISIS or if their militias were overrun by the rival group. But according to the British-based Syrian Observatory for Human Rights, one of the only human rights groups monitoring the fighting in the country, it was the former -- which could signal that ISIS is gaining support from the biggest radical Muslim fighting group in the Syrian civil war.

At this point, however, any deal of this type has not evolved into a partnership; al-Qaeda leaders have said they did not support ISIS, and that al-Nusra is their legitimate representative in Syria.

As ISIS advances in Syria, leaders of the Syrian National Council (SNC) -- the umbrella group that encompasses what the U.S. has designated as the “moderate opposition” -- are left wondering what else they can do to fight not only President Bashar Assad’s forces, but an increasingly powerful ISIS. The council is meeting this week in Istanbul to elect a new president and strategize about how to confront the rapid advancement of the militant group.

The SNC is recognized by seven U.N. member nations, including three permanent members of the Security Council, the U.S., France and the U.K. In 2011, then-Secretary of State Hillary Clinton said the SNC was a “leading and legitimate representative of Syrians seeking a peaceful democratic transition,” and that the U.S. was “committed to helping … make this transition.”

In addition to voting for a new president of the organization, the coalition will also elect three vice presidents, a secretary general and a political committee, according to a statement by the group.

The meeting in Istanbul comes just two weeks after President Obama announced that he would ask Congress for an additional $500 million to arm and train the moderate opposition in Syria. A White House statement said rebels would be “appropriately vetted” before receiving the assistance.

Obama first announced the existence of a CIA-led program in Syria that arms and trains the select opposition groups that comprise the Free Syrian Army (FSA) June 13, 2013. At the time of the announcement, senior U.S. politicians said they worried the weapons would fall into the “wrong hands."

For months, amid escalating violence in Homs and Aleppo, the Obama administration refused to send heavier weaponry, such as portable antiaircraft missiles, to Syria, fearing they would eventually land in the hands of groups that would use them against the West. In the 1980s, the U.S. armed the Afghan mujahedeen, who were fighting the Soviet troops that had invaded the country. Those weapons, including very dangerous antiaircraft missiles, ended up in the hands of the Taliban, and they were used against U.S. troops when they invaded the country in 2001.

The opposition has asked U.S. and European leaders to pledge more arms and money to help fight Assad’s forces. That plea intensified as ISIS advanced in Iraq, seizing army weapons there and opening the border with Syria. The opposition now has to fight on two fronts, against Assad and against ISIS, and it has to worry about fighting a militant group that has access to stockpiles of newly acquired, powerful arms.

Senior opposition officials in the FSA said ISIS transported Humvees, helicopters and smaller arms such as Kalashnikovs through the border to Syria after the takeover of Mosul, Iraq’s second largest city. The helicopters in particular are the most useful to the extremist group as they would allow the militants to fight from the air, something no anti-Assad group has been able to do throughout the three-year war.

Syrian opposition officials spoke via Skype at a press conference in Washington, D.C., on June 12, including Col. Abdul-Jabbar Akidi, who led FSA forces when they first entered Aleppo in 2012; Col. Afif Suleiman, head of FSA forces in Idlib; and Mustafa Berro, the leader of a coalition of rebel groups designated to fight ISIS. They said they were “extremely worried” ISIS would be able to mount a stronger offensive against the moderate opposition in Syria.

Obama’s recent request from Congress would formulate an initiative that would most likely train fighters from the opposition in a location outside of the country, in places such as Jordan. The initiative would be part of the “Counter Terrorism Partnerships Fund” that Obama proposed during his commencement speech at West Point in May.

He said the U.S. would "ramp up support for those in the Syrian opposition who offer the best alternative to terrorists and a brutal dictator." Congress has yet to approve the request, and it is unclear when this would take place.

A more solidified Syrian opposition is likely to assuage fears by members of Congress who do not trust its credibility or its ability to crush Assad’s forces. The Syrian opposition has in past years struggled to define a leadership structure that had the capacity to negotiate with the international community.

This is the third time the group has elected a president since 2012. When the coalition formed, it elected Moaz al-Khatib, a former imam of the Umayyad Mosque in Damascus. In March 2013, al-Khatib stepped down after he bypassed the coalition and offered to negotiate with the Syrian government -- an initiative pushed for by then-U.N. envoy for Syria Lakhdar Brahimi. Al-Khatib later claimed that the coalition did not have a clear mission and engaged in frustrating conversations with Saudi Arabia and Qatar. Ahmad al-Jarba, the current president of the coalition, was elected in July 2013 and has served two six-month terms, the maximum period allowed by the coalition.