IS militants make fresh Syria advance

The Islamic State (IS) on Sunday seized an army position in the northeast Syrian city of Hasakeh, amid a major escalation in the militant offensive, a monitor said.

On another front in Syria's complex civil war, rebels seeking President Bashar al-Assad's ouster captured a weapons depot in Hama province, said the Syrian Observatory for Human Rights.

Just south of Hasake city, "IS jihadists took over the army Regiment 121 at Maylabiyeh, after fierce clashes with regime troops", said the Britain-based Observatory, adding that the battle lasted three days.

On twitter, supporters of IS, which first emerged in Syria's war in spring 2013, celebrated the army position's "liberation" at the hands of the militants.

The latest advance comes a day after IS took over Division 17 in Raqa province. According to the Observatory, at least 85 regime troops were killed during the IS takeover, among them more than 50 who were executed after their capture.

But also on Saturday, pro-Assad recaptured the Shaar gas field in Homs province. The field had fallen into IS' hands nearly two weeks ago, and the militants killed some 270 guards, pro-Assad paramilitary and civilian employees there.

While IS has escalated its offensive against the army in some parts of Syria in the past fortnight, it has been at open war against rebels seeking Assad's ouster since January.

On another front, rebels in Hama province captured Khattab and Rahbeh villages, taking over arms depots there, said Observatory director Rami Abdel Rahman.

Rebels, he added, are now "advancing towards Hama military airport", which is a key army position and home to one of the country's most feared prisons.

Amateur video posted by activists on YouTube showed some of the weapons seized by the rebels in Hama, among them rockets, ammunition and mortars.

The Observatory meanwhile said the toll from a Saturday car bomb in Atme, on the Turkish border, rose to seven, among them an Islamist rebel commander.

Another seven were killed in a separate car bomb on Saturday in Azaz, also on the Turkish border, the group said.

Syria's war has killed more than 170,000 people in three years, and forced nearly half the population to flee their homes.