KABUL — U.S. military deaths in Afghanistan doubled in 2009 compared with a year ago as 30,000 additional troops began pouring in for a stepped-up offensive and the Taliban fought back with powerful improvised bombs.

A tally by The Associated Press shows 304 American service members had died as of Dec. 30, up from 151 in 2008. The count does not include eight U.S. civilians killed by a suicide bomber on a base in eastern Afghanistan on Wednesday.

Also, the annual death toll of international troops, including U.S. forces, surpassed 500 for the first time in the war. The total this year was 502 compared with 286 in 2008, according to the AP count.

Among other forces, Britain took the worst blow in 2009 with 107 deaths and Canada lost 32, including four who died Wednesday when their vehicle was blown up by a roadside bomb. Other countries in the international military operation lost 59 service members.

U.S. military officials acknowledge the insurgency has the momentum and more troops on the battlefield means the death toll is likely to remain high in the near term. Another 30,000 reinforcements are due in coming months, raising the American presence to 100,000.

In contrast, U.S. deaths in Iraq dropped by half as troops largely remained on bases and the United States prepares to withdraw from that country by the end of 2011. There, 152 American service members died, down from 314 a year earlier, according to figures compiled by the AP from U.S. Defense Department information.

The rising death toll in Afghanistan was an obstacle for President Barack Obama as he decided in November to send more forces to the war, which is increasingly unpopular in America and Europe.

according to the United Nations mission in Afghanistan, 2,021 civilians were killed in the first 10 months of the year, nearly 1,400 of them by insurgents and 465 by U.S. and other pro-government forces.

Over the past eight years, at least 933 U.S. service members have died in the military campaign that was launched in the wake of the Sept. 11, 2001, attacks, according to U.S. Defense Department figures that include deaths in Pakistan, Uzbekistan and support operations elsewhere.

The AP count, based on daily reports from NATO's International Security Assistance Force, found that 129 of the U.S. fatalities in 2009 — or more than 40 percent — were caused by improvised explosive devices, or IEDs. The homemade bombs are hidden along the roadside or near buildings and detonated by remote control or triggered when troops cross simple pressure plates.