Four Iraqi civilians were killed and 30 others wounded, including two children, when their houses were struck by eight mortar rounds in al-Qaim on Saturday, Aljazeera said. It is not yet clear who had fired the mortar shells.
Elsewhere in the city, the US military said a car bomb killed three US troops and an Iraqi civilian. The military also said a US soldier died after a car-bomb blast in Mosul earlier in the day.
Late on Saturday evening, US military sources confirmed that two US transport helicopters had crashed in Iraq with two soldiers reported dead and two wounded.
In another incident near the Syrian border, an unknown group seized Colonel Asad Musharraf, the chief of police in Rutba city.
Meanwhile, Aljazeera reported three Iraqis were killed and a child injured when US troops opened fire on their vehicle near Abu Ghraib prison, west of Baghdad.
South of Baghdad, a group of armed fighters attacked three US trucks hauling military vehicles near the Salman Bek district. The trucks were destroyed in the attack.
One hospital worker at Ibn al-Bitar hospital in central Baghdad was killed and at least three others injured in an explosion that occurred shortly after 9am (0600 GMT) on Saturday.
Elsewhere in the city, a rocket struck the car park of the Mansur Hotel - used by foreign news organisations and diplomats - damaging vehicles but causing no casualties.
The Association of Muslim
Scholars condemned the attacks
The explosion shattered glass in the lobby, said Bian Zhiqiang, interim charge d'affaires for the Chinese embassy, which is located inside the hotel.
A US soldier at the scene said an investigation to identify the type of rocket used and where it had been fired from was under way.
The Baghdad blasts followed overnight bomb attacks that damaged five churches in the capital, but caused no casualties.
The blasts rang out in quick succession over an hour and a half, starting at 4am (0100GMT) at St Joseph Church in the Nafaq al-Shurta area, Aljazeera reported.
The churches all suffered
The other churches hit were St Jacob's Church and St George's Church in the Dura neighbourhood, the Church of Rome in the Karrada neighbourhood and St Thomas Church in the Mansur area.
Video footage showed considerable exterior damage, with windows blown out and a dome of one of the churches all but destroyed.
In August, coordinated attacks hit four churches in Baghdad and one in Mosul, killing at least seven people and wounding dozens more in the first strike against Iraq's minority Christians since the US invasion began last year.
The influential Association of Muslim Scholars condemned the attacks.
Three Iraqis from the same family were killed in a roadside bomb blast outside the city of Baquba, north-east of Baghdad, local police said on Saturday.
The men, two brothers and a cousin, were found dead in an orchard in Mansuriyat al-Jabal, about 45km outside Baquba after the explosion at 6pm (1500GMT) on Friday, police said.
Local authorities have opened an inquiry to establish whether the blast was the result of a criminal attack or a bomb that had detonated by mistake.