BAGHDAD, Iraq - U.S. Marines killed 25 insurgents and captured 25 others during several hours of fierce fighting in Ramadi, a hotbed of insurgents battling U.S. and Iraqi forces, the American military said Thursday.

The fighting Wednesday in Ramadi, 70 miles west of Baghdad, wounded 14 U.S. servicemen, but none sustained life threatening injuries and 10 have returned to duty, according to a Marine statement.

Meanwhile today, Indian officials in Baghdad were working with Egypt and Kenya to free six of their nationals whose kidnapping was announced Wednesday, an Indian official said from New Delhi on condition of anonymity.

The group that captured the six said it would behead a captive every 72 hours beginning Saturday night if their countries do not announce their intentions to withdraw troops and citizens from Iraq and warned that every Kuwaiti company dealing with Americans "will be dealt with as an American."

The threat came two days after the Philippines withdrew its 51 troops from Iraq, giving in to the demands of militants holding a Filipino truck driver. The driver, Angelo dela Cruz, returned to the Philippines today, two days after his release.

Iraqi and U.S. officials had warned of a potential surge in threats and hostage-taking when the Philippines withdrew its troops. Egypt, Kenya and India are not part of the 160,000-member U.S.-led coalition; however, interim Iraqi Prime Minister Iyad Allawi appealed last week to India and Egypt to send in troops.

The daylong clashes in Ramadi began after insurgents detonated a roadside bomb near a Marine convoy at about 3 p.m. on Wednesday in an ambush attempt. Between eight and 10 Iraqi fighters then attacked the Marines with small arms and rocket propelled grenades.

"This initial skirmish led to ensuing engagements that pitted elements of the (U.S. Marines) 1st Brigade Combat team ... against what is being estimated as at least 75-100 AIF," the statement said.

Backed by U.S. warplanes, the American ground forces clashed with the insurgents for hours, during which the Marines also safely detonated two homemade bombs, including one placed in a car.

The statement said 25 insurgents died in the fighting and another 17 were wounded.

There were no immediate reports of U.S. deaths today. On Wednesday, the death toll of American troops in Iraq since the start of the war rose to 900 after a roadside bomb north of Baghdad killed one U.S. 1st Infantry Division soldier.

India on Thursday called for the swift release of the three Indian truck drivers captured with the two Kenyans and one Egyptian, saying the three had nothing to do with the war.