By Michael Georgy

KABUL, Afghanistan, Feb 23 - The number of American soldiers killed in Afghanistan has reached 1,000, an independent website said on Tuesday, a grim reminder that eight years of fighting has failed to defeat Taliban insurgents.

Icasualties.org said 54 U.S. troops were killed this year in Afghanistan, raising the casualties to 1,000, compared to eight in Iraq, where the total has reached 4,378.

The rise to 1,000 dead coincides with one of the biggest offensives against the Taliban, a NATO-led assault in the Marjah district of Helmand, Afghanistan's most violent province.

The operation is an early test of U.S. President Barack Obama's troop surge strategy aimed as wresting control of Taliban bastions and handing them over to Afghan authorities before the start of a gradual U.S. troop withdrawal in 2011.

Afghanistan is high on Obama's foreign policy agenda and more American casualties or a military campaign that fails to bring stability to the country could harm his presidency.

Violence is at its highest level since the 2001 ouster of the Taliban. Last year was the deadliest of the war for civilians and foreign troops.

Marjah is a prime example of the challenge facing U.S. troops and their NATO allies.

They have taken over key areas, but still face pockets of stiff resistance from the Taliban, who have littered roads with hidden bombs.

The success of the operation hinges on whether they can keep Taliban fighters from re-capturing their stronghold and ensure Afghan forces can secure the area on their own.

Ultimately Marjah can only be stable once the local government provides enough jobs and economic opportunities to keep the local population on its side, eradicating conditions that breed militancy, analysts say.

Obama announced in December he was adding 30,000 more U.S. troops to the Afghan war effort.

He hopes to start bringing U.S. troops home from Afghanistan in the middle of 2011.