Syrian activists say more than 630 people have been killed and at least 130,000 have been displaced in more than a month of rebel infighting in an eastern province near the Iraqi border, AP reported.
The Britain-based Syrian Observatory for Human Rights says 39 civilians are among the 634 people killed in Deir el-Zour province since April 30.
The fighting is between Islamic rebel battalions and the al-Qaida breakaway group known as the Islamic State of Iraq and the Levant.
The Observatory said Tuesday the tally includes 354 rebel fighters, including many from the al-Qaida-affiliated Nusra Front, and 241 gunmen from the Islamic State.
Islamic rebels and more moderate factions have been locked in a brutal fight against the Islamic State across opposition-held northern Syria since early January.