(Reuters) – Explosions damaged churches in Baghdad on Saturday and the U.S. military reported the deaths of four more American troops in bomb attacks elsewhere in Iraq. A suicide car bomber killed three U.S. troops, along with an Iraqi civilian, in Qaim near the Syrian border on Friday. The fourth died after a car bomb blast in Mosul the same day. A mortar attack on Qaim killed four Iraqis and wounded 30 on Saturday, a local hospital doctor said. In another challenge for the U.S.-backed interim government, a group led by Jordanian militant Abu Musab al-Zarqawi vowed to attack foreign trucks bringing petrol and diesel into Iraq. Five churches were hit in a string of bomb attacks before dawn that seemed designed to intimidate the country’s small but deep-rooted Christian community, already shaken by a deadlier series of bombings of churches that killed 11 people in August. “If they don’t want us in Iraq, let them say it and we will leave,” said Samir Hermiz, 40, standing by a Catholic church reduced to ashes. “I’m really thinking of leaving Iraq.” Iraq’s 650,000 Christians, about three percent of the population, are mostly Chaldeans, Assyrians and Catholics.