Obama writes to CIA, marking death of 7 staffers in Afghanistan

WASHINGTON, Dec. 31 (Xinhua) -- U.S. President Barack Obama wrote to the Central Intelligence Agency on Thursday, marking the death of seven agency workers in a suicide blast Wednesday in Afghanistan, one of the deadliest known attacks on the spy agency, the White House said.

Saying the attack was a "sad occasion" in the history of the CIA and the United States, Obama noted the spy agency as been tested as never before in recent years since the 9/11 attacks in 2001, confronting dangers of the 21st century directly.

He said the work of CIA has disrupted plots and saved lives of Americans, and at the same time made U.S. allies more secure, according to the White House.

The workers were killed in a suicide blast Wednesday in CIA post Camp Chapman in Khost Province, southeastern Afghanistan. Although details of the attack were sketchy, reports have indicated those killed include CIA's chief of operation at the post, who's in charge of intelligence gathering and agency operation coordination in the province.

The Taliban has claimed responsibility of the attack, saying an Afghan National Army officer wearing a suicide vest entered the base and blew himself up inside the gym. Agency officials have vowed to avenge the attack through aggressive counter-terrorism operations, according to media reports.

U.S. officials have earlier said 8 civilians were killed in the attack. Voice of America said an American working for the State Department was also killed in the attack. Six others were injured.

Prior to the attack, there were only 4 known CIA operatives died in Afghanistan since Sept. 11, 2001, reports have suggested.