China is condemning the killing of at least 11 Chinese workers in Afghanistan.

Assailants attacked a compound in the northern Afghan city of Kunduz, where the Chinese workers were staying. Afghan officials say gunmen with automatic rifles burst into the compound and opened fire on the sleeping workers.

The contractors were working on road projects as part of a large scale, internationally funded plan to rebuild the war-torn country.

Chinese Foreign Ministry spokesman Liu Jianchao said Beijing is asking for an investigation.

"Chinese leaders, after learning the news, strongly condemned this brutal terrorist act," he said.

Witnesses say it was one of the most deadly attacks on foreigners since the fall of the Taleban government more than two-years ago. The Taleban were accused of harboring terrorists, including Osama bin Laden.

No one has claimed responsibility for the assault, and Chinese officials on Thursday would not speculate on why Chinese nationals were targeted.

But the Taleban and al-Qaida have been killing foreigners since the U.S.-led war on terror ousted the Taleban government in 2001.

Hundreds of Chinese construction workers are in Afghanistan, with more than 120 working on the Kunduz project.

China was among the supporters of the U.S.-led war, but it strongly opposed later military action in Iraq.