In what would mark the bloodiest two days of fighting in the Syrian civil war, more than 700 people were reported killed in fighting between government and rebel forces loyal to the radical Islamic State (IS) — more than have been killed during the 15-day-old Gaza conflict that has dominated media attention in recent days.

The two-day death toll occurred last Thursday and Friday, with brutal fighting between forces loyal to President Bashar al-Assad and the IS that centered around a gas field, according to reports released this week from the Syrian Observatory for Human Rights, a British-based anti-Syrian government group that keeps tabs on the war’s dead.

The Islamic State reportedly captured the Shaar gas field east of the city of Homs on Thursday. The Syrian Observatory was not able to say how many victims were members of government troops or rebel forces.

IS, a one-time ally of Al-Qaeda, has gained prominence in recent months for its harsh interpretation of Islamic law and battlefield successes in Syria and neighboring Iraq, where it has had a string of successes against the Iraqi government. IS is trying to establish an Islamic caliphate in the region, and its leader, Abu Bakr al-Baghdadi, recently declared himself caliph.

For several months, the Assad government has held the upper hand against Syrian rebels, which have become increasingly fractured. That reality was underscored Tuesday, when the Western-backed Syrian National Coalition said it had voted to force out its "interim government" and form a new one within a month.

Attempts to form a viable government-in-exile for Syria's opposition have been hamstrung by internal rivalries and by its inability to establish itself inside Syria.

The Syrian National Coalition is designated as the main body representing the opposition by the United States and other major powers, but it has little influence over rebels fighting to overthrow Assad.

The group said in a statement on Tuesday it was dissolving its interim cabinet to "create new ground for work on the basis of moving the government into the interior as soon as possible, and employing Syrian revolutionary capabilities.”

The group’s dissolution comes two weeks after it elected Hadi al-Bahra, a U.S.-trained industrial engineer, to replace its president, Ahmad Jarba, after he served his maximum two six-month terms.

So long as the opposition remains divided, a number of analysts have suggested that besides benefiting the Assad government, it may also bode well for IS prospects in Syria.

“The potential for ISIS [another name for the Islamic State] to engineer a similar resurgence in Syria [as Iraq] is real,” wrote Noah Bonsey, an analyst with the International Crisis Group, in the Huffington Post.

“Should it succeed, ISIS would be well-positioned to present itself to Sunnis in the region at large as the only remaining force with the strength to oppose reviled regimes in Baghdad and Damascus.”

Al Jazeera and Reuters