Syrian militants surrounded a compound held by al-Qaida-linked fighters and freed at least 50 people from a nearby prison Monday as clashes between rival factions in the country's northern provinces spread to the largest city controlled by the opposition.
The militant-on-militant fighting in Raqqa - a stronghold of the al-Qaida-linked group known as the Islamic State in Iraq and the Levant - reflects a widening war within a war in Syria, this one against radical extremists. It also adds yet another layer of complexity to the broader Syrian conflict less than three weeks ahead of a planned international peace conference to try to broker a political solution.
Support from the U.S and its Western allies for the militants has faded in the past year as al-Qaida-affiliated groups have risen to become one of the most dominant forces among the patchwork of opposition fighting factions.
There was no indication that the move by a mix of more secular militants and powerful ultraconservative Islamist brigades against the al-Qaida fighters was a reaction to Western pressure to move against the extremist group. Rather, the violence has been largely limited to communities where tensions between the factions were already simmering.
The number of towns, villages and neighborhoods where clashes were taking place spread across four provinces, providing an indication of the extent of resentment of the Islamic State in Iraq and the Levant.
Since spring 2013, the group has muscled its way into militant-held territory across northern Syria, crushing resistance from other factions, seizing their weapons and detaining their fighters. It has kidnapped journalists and abducted activists who are critical of its efforts to impose a strict interpretation of Islam.
For months, sporadic clashes between its fighters and other militant brigades have left scores dead .
But the latest fighting, which broke out Friday in the northern provinces of Aleppo and Idlib after residents there accused the al-Qaida-linked group of killing a popular doctor, is the most serious.
The fighting has since spread to the central province of Hama as well as the northeastern province of Raqqa, and killed an estimated 100 fighters on both sides,
The fighting in the city of Raqqa - the provincial capital - began before dawn Monday, when a coalition of Islamic brigades attacked fighters from the Islamic State in Iraq and the Levant. The Raqqa clashes, saying they were focused around a post office.
The Islamic State in Iraq and the Levant retreated from the town of Tal Abyad along the Turkish border after heavy fighting there. Clashes continued in parts of Aleppo province, including the neighborhoods of Masaken Hanano and Shaar in the city of Aleppo.
Another al-Qaida-linked rebel group, al-Nusra Front, was taking part in the fighting in Raqqa against the Islamic State in Iraq and the Levant. However, many of the al-Nusra Front fighters in Raqqa had joined the group from other militant outfits that had collapsed in the face of the Islamic State in Iraq and the Levant.