Toll surges in Syria after recent fighting

More than 2,000 Syrians have been killed in just over two weeks of fighting in Syria, an especially deadly period in the country's three-year civil war, according to the Syrian Observatory for Human Rights.

Nearly half of the deaths were soldiers and government-allied militiamen, SOHR said. 

"These are the highest losses for regime forces suffered in the space of 10 days since the uprising against Assad began" in March 2011, said Rami Abdurrahman, director of London-based SOHR.

The group documents losses on both sides of the conflict through a network of activists on the ground in Syria. It didn't provide a breakdown of civilians and opposition casualties.

The report reflects a recent surge in deadly attacks by the Al-Qaeda-breakaway group, Islamic State, which is targeting President Bashar al-Assad's forces, signaling shifting priorities as the rebels seek to consolidate their hold on territory and resources in northern Syria.

Assad's forces have gained momentum in the fighting with Sunni rebels whose cause has been hurt by infighting.

But the Islamic State threatens to overturn government successes as the Syrian army now faces a formidable force in control of large areas in northern Syria and neighboring Iraq. 

Assad was re-elected last month to a third, seven-year term in a vote that was confined to government-controlled areas and dismissed by the opposition and its Western allies. In his inauguration speech on July 16, he confidently declared victory and praised his supporters for "defeating the dirty war."

Since then, Islamic State fighters have launched attacks against Syrian army positions in three provinces in northern and central Syria. In the past week alone, the group has captured a government-controlled gas field and two major army bases in three different provinces. 

The Syrian army on Sunday recaptured a gas field east of the central city of Homs that was seized by fighters from Islamic State group earlier this month.

Opposition activists told Al Jazeera the recapture of Shaer field dealt a blow to the Islamic State.

"The Shaer field is an important military base that the army used to protect nearby villages that are loyal to Assad," opposition activist Mahmoud al-Homsi told Al Jazeera via Skype from Homs.

Meanwhile, the Islamic State has opened an office in northern Syria where single women and widows can register to marry fighters, according to SOHR.

The office in al-Bab, a town northeast of Aleppo, records the names and addresses of the women so that Islamic State fighters can go to their families and make a formal offer of marriage, SOHR said. The Observatory, cited sources in al-Bab and Aleppo. It was not possible to independently confirm the report.

There have been previous reports of fighters seeking wives or forcing women to marry them in areas where the group has been active but this is the first time Abdurrahman said he had heard of the group setting up a formal office to register potential spouses. The Islamic State has set strict limits on women's rights in areas it controls.

In a separate development, Assad made his first appearance in public after being sworn in as president when he attended prayers at a Damascus mosque to mark the start of the Muslim holiday of Eid earlier on Monday. 

Assad was filmed by Syrian TV on Monday at the prayer in al-Kheir mosque in the capital with Syria’s grand mufti, Mohammad Hassoun, and senior officials in the government.

Al Jazeera and wire services