Four children collecting trash were killed Friday by a homemade bomb in Baghdad, and masked gunmen killed an Iraqi Army officer in a restaurant in Basra, police said. The children died in the New Baghdad neighborhood in the southeast section of the city, police Capt. Sabah Hamid Al-Fartosi said. Insurgents frequently use hidden roadside bombs against U.S. and Iraqi Army convoys. Three masked gunmen killed an Iraqi Army officer, Maj. Mahmoud Hassan Al-Yassiri, late Thursday in the southern city of Basra, Capt. Firas al-Timimi of the Iraqi Army said. In Najaf, four civilians were injured by a bomb that exploded near a bus station, local police Capt. Qussai al-Jazaeri said. Also Friday, police in Kirkuk, about 180 miles (290 kilometers) north of Baghdad, said one driver was killed in an attack that set several Turkish oil tankers ablaze the prior night. Six others were wounded.