The number of U.S. service personnel killed in Afghanistan since military operations began in 2001 has reached 1,000, the icasualties.org web site reported on Tuesday.

The independent site tracks losses suffered by international military forces in Afghanistan and Iraq. It said the 1,000 death occurred on Monday, citing a U.S. military command announcement on the death of a soldier in southern Afghanistan.

U.S. troops have been fighting in Afghanistan since 2001, when the Taliban government was overthrown in response to its sheltering of Al Qaeda after the September 11 attacks on the United States.

President Barack Obama has sent thousands of additional troops to the country since taking office last year, in an effort to reduce violence and pave the way for a withdrawal, but 2009 was the bloodiest year yet for U.S. forces, with 316 fatalities, and 54 have died already this year.

Britain and Canada are the only other nations to have lost more than 100 personnel in the nine-and-a-half-year campaign, with 264 and 140 deaths, respectively.