Also Saturday, the U.S. command said four more American troops and an Iraqi interpreter were killed the day before by car bombs in the west and north of the country.
U.S. jets struck again in the rebel stronghold of Fallujah, blasting what the American command said was a checkpoint operated by the feared Tawhid and Jihad terror movement of Jordanian-born extremist Abu Musab al-Zarqawi. Three people were killed, according to a hospital in Fallujah.
The military action occurred despite an offer by community leaders in Fallujah to resume peace talks with the government if U.S. forces stop their attacks on the city and free their chief negotiator.
Fallujah hospital officials also said U.S. artillery shells fell on a house in Halabsa village, 10 miles southwest of the city, on Saturday killing a 3-year-old girl and injuring four family members.
Mortar shells exploded Saturday near Ibn al-Betar hospital, killing one employee and wounding three others, and also in the parking lot of the Mansour Hotel, which houses the Chinese embassy and is home to foreign diplomats and journalists. No one was killed in the hotel attack.
The Army helicopters went down about 8:30 p.m. in southwestern Baghdad, the 1st Cavalry Division said. The division said the cause of the crashes had not been determined.
The U.S. military has lost at least 27 helicopters in Iraq since May 2003, many of them to hostile fire, according to the Brookings Institution.
Homemade bombs exploded in quick succession before dawn at the five churches in four separate Baghdad neighborhoods. They inflicted no casualties but further alarmed the Christian minority community already on edge over the perceived rise of Islamic militancy after last year's ouster of Saddam Hussein.
In August, coordinated attacks hit four churches in Baghdad and one in Mosul, killing at least 12 people and wounding dozens more in the first significant strike against Iraq's estimated 800,000 Christians since the U.S. invasion began last year.
''It is a criminal act to make Iraq unstable and to create religious difficulties,'' the Rev. Zaya Yousef of St. George's Church said of the latest attacks. ''But this will not happen because we all live together like brothers in this country through sadness and happiness.''
No group claimed responsibility for the attacks, which were condemned by the Association of Muslim Scholars, a Sunni clerical group believed to have ties to some insurgents.
''Islam doesn't support the ongoing terrorism,'' Sheik Abdul Sattar Abdul-Jabbar of the association said.
Three U.S. troops - two soldiers and one Marine - were killed Friday when a car bomb exploded near Qaim, an insurgent hotspot along the Syrian border, the U.S. command said. An Iraqi interpreter was also killed.
A fourth soldier, assigned to Task Force Olympia, died of injuries suffered Friday during a car bombing in the northern city of Mosul, 225 miles north of Baghdad, the U.S. command said Saturday.
U.S. commanders have warned of a possible increase in rebel attacks during Ramadan, when insurgent activity surged last year. Ramadan, the month of fasting and prayer, is marked by greater religious fervor, and some extremists believe they win a special place in paradise if they die fighting non-Muslims during the holy month.
