ISIS Militants Capture Air Base From Syrian Government Forces

BAGHDAD - Extremist fighters from the Islamic State in Iraq and Syria seized a military base in northern Syria on Sunday from forces loyal to President Bashar al-Assad, further solidifying control inside their self-declared Islamic state spanning the Syria-Iraq border.

The fall of the Tabqa air base followed the group's seizing of two other Syrian military bases and gave it effective control of Raqqa Province, which abuts the Turkish border and whose capital city, Raqqa, has long served as the group's de facto headquarters.

Recent military advances by ISIS in northern and eastern Syria have highlighted the lack of local military forces that can effectively battle the group, which President Obama last week called a 'cancer' that must be eradicated from the Middle East.

Syrian rebel groups that formed to fight Mr. Assad's government never managed to take the air base, and while Mr. Assad's forces have been bombing ISIS from the air and killing its fighters, they lack the ground troops necessary to challenge the group's hold on terrain.

The United States began airstrikes on ISIS positions in Iraq this month, leading to some advances by Iraqi and Kurdish forces. But Mr. Obama has declined to intervene in Syria's civil war.

The Syrian Observatory for Human Rights, which tracks the conflict from Britain through a network of contacts inside Syria, said ISIS' attack on Sunday was its fourth in the past week. The Syrian government had launched airstrikes on ISIS positions, but the group's fighters managed to enter the grounds of the air base on Sunday and took it over after many of the troops inside withdrew.

More than 340 ISIS fighters have been killed since the start of the offensive on Tuesday, the Observatory said, in addition to about 170 government soldiers. If confirmed, those numbers would make the battle the deadliest yet between the jihadist movement and the Syrian government.

Photographs posted Sunday on Twitter accounts sympathetic to ISIS showed bearded fighters in the air base, standing next to a destroyed fighter jet and appearing to cut the head off a dead soldier.

The Observatory and an antigovernment activist reached through Skype nearby said that all the working aircraft had been flown out of the base before ISIS stormed in.

The Syrian state news service, SANA, acknowledged that government troops had withdrawn from the air base but said they had successfully 'regrouped' and were still fighting nearby.