The U.S. military in Iraq says troops killed 30 suspected militants and detained 12 others during raids on an alleged international bomb-smuggling network inside Baghdad's Shi'ite Sadr City neighborhood.
A military statement says the "Special Groups" terrorist network smuggled Iranian-made armor-piercing explosive devices and moved militants from Iraq to Iran for training.
Iraqi police said some of those killed in Wednesday's operation were civilians.
The raid came as Iraqi Prime Minister Nouri al-Maliki arrived in Iran for security talks.
U.S. officials have accused Iran of providing support for Shi'ite militants in Iraq. Tehran denies the charge and says the U.S. presence in Iraq worsens the country's insurgency.
In other developments, Iraqi authorities imposed a vehicle curfew in Baghdad for three days, to guard against insurgent attacks during a major Shi'ite religious event.
Hundreds of thousands of Shi'ites are expected to converge on the shrine of Imam Moussa Kadhim for the commemoration of his death 12 centuries ago.
Also Wednesday, the British Ministry of Defense said a British soldier was killed Tuesday in the southern Iraqi port city of Basra. The U.S. military said a roadside bomb killed a U.S. soldier in Baghdad Tuesday.
In Washington, the newspaper "USA Today" says the defense department has asked Congress for nearly $750 million to airlift new armored vehicles to U.S. troops facing roadside bombs in Iraq.
The report says the emergency funding request will allow the military to fly many of the Mine Resistant Ambush Protected vehicles directly to troops rather than send them by ship, which takes weeks.
U.S. officials have said most of the vehicles that American troops use in Iraq are vulnerable to armor-piercing roadside bombs.
