Extremists join Syrian rebels, worrying U.S.

BEIRUT — Syrian rebels including Islamic extremists took control of a military base Tuesday after a bloody two-day battle that killed 35 soldiers, activists said. It was the latest gain by opposition forces bolstered by an al-Qaida-linked group that has provided skilled fighters but raised concerns in the West.

The Sheik Suleiman military base was the second major base captured in the north by the rebels, who are making inroads farther south toward Damascus.

In other violence, dozens of people were reported injured or killed in Aqrab in a series of explosions. The Britainbased Syrian Observatory for Human Rights reported the bloodshed, citing activists in the area, but had no death toll or details on who was to blame.

Fighters from jihadi groups, including Jabhat al-Nusra, were among those doing battle in the rebel ranks as they took control of Sheik Suleiman base, according to the Observatory and other activists.

The presence of the jihadi groups has raised concerns in the United States and other nations that are supporting the opposition in Syria. The United States this week blacklisted al-Nusra as a foreign terrorist organization and said the group was part of al-Qaida in Iraq.

The terror designation freezes any assets members of al-Nusra may have in U.S. jurisdictions and bars Americans from providing material support.

The administration took further action Tuesday against extremists on both sides, with the Treasury Department setting separate sanctions against two al-Nusra leaders and two militant groups operating under the control of Syrian President Bashar Assad’s government. Two commanders of the pro-regime shabiha force also were targeted.

“We will target the pro-Assad militias just as we will the terrorists who falsely cloak themselves in the flag of the legitimate opposition,” said David S. Cohen, the department’s sanctions chief.

Jabhat al-Nusra is a group with an al-Qaida-style ideology whose fighters include veterans of previous wars who came to Syria for what they consider a new “holy war” against Assad.