Washington ? U.S. military deaths in Iraq during March hit a two-year low, even as religious and ethnic violence between Iraqi factions skyrocketed.

According to Pentagon statistics, 30 American service members died during the month, the lowest level since February 2004, when 20 troops died. All but four of the deaths were by hostile fire.

The number of deaths attributed to roadside bombs, which remain the overall top killer of U.S. forces, was 12, the lowest in a year.

American military officials credited the drop to improved performance of Iraqi security forces in recent weeks and better training of U.S. troops.

“What I would tell you is the Iraqi security forces’ capability is getting better,” said Army Maj. Gen. James Thurman, the commander of coalition forces in Baghdad. “And I attribute : a lot of the decline in our fatalities (to) the alertness and the training levels of our soldiers.”

But some analysts said the nature of the war had changed, with Iraqi factions now attacking one another rather than American forces.

Iraqi men carry the coffin of a 4-year-old girl who was killed when a car bomb exploded near the Shiite Ali Basha mosque Friday March 31, 2006 in Baghdad's eastern Kryaat neighborhood. A mortar round slammed into a street in northeastern Baghdad Friday, as Iraqi leaders, trying to form a national unity government, resumed talks.

“What you have is the insurgents are trying to block the formation of a coalition government and trying to cause a civil war,” said Anthony Cordesman, a former Pentagon official who’s now an analyst at the Center for Strategic and International Studies in Washington. “That means that a lot of these attacks now focus on Iraqi civilians.”

U.S. fatalities in Iraq reached a 12-month high in October, when 96 service members died.

Statistics released by the American-led coalition show that the number of Iraqis killed in violence has zoomed since the Feb. 22 insurgent bombing of the Askariya mosque in Samarra, an important Shiite Muslim shrine.

More than 1,300 Iraqis have died in retaliatory killings between Sunni Muslim and Shiite groups since the mosque bombing. Nearly 1,000 of those deaths were in Baghdad, according to the statistics.