BAGHDAD - An Iraqi interpreter for the US military was gunned down on Friday by his son and nephew north of the capital after he refused their demands to quit his job, a police official said. The attack occurred as at least 27 people were killed nationwide, a grim reminder of the dangers facing Iraqis despite a sharp drop in violence over the past few years. In the deadliest attack, insurgents ambushed a checkpoint near the Syrian border, killing seven Iraqi soldiers and wounding an eighth. Hameed al-Daraji, who had worked as a translator for the U.S. military since 2003 against the wishes of his family, was shot in the chest in his house in Samarra, 60 miles (95 kilometers) north of Baghdad, police Lt. Emad Muhsin said. He said al-Daraji was constantly fighting with his relatives over his job, but he ignored their pleas for him to quit. Al-Daraji's son and nephew were arrested after the attack and confessed to being members of an al-Qaida-linked group that sanctioned the killing, Muhsin said, adding that police were searching for a second son suspected of being an accomplice. Iraqis working for the U.S. military in the country have been targets of extremist groups who view them as traitors and collaborators with an invading country. But it is rare for family members to kill a relative because of his or her employment with the Americans in Iraq. The seven Iraqi soldiers were killed by a group of gunmen who pulled up to the checkpoint near the Qaim border town in pickups and opened fire, according to police, hospital and provincial officials. They say the gunmen shot an eighth soldier several times but left him alive "to convey a message to the Iraqi army." The area in which the attack occurred is in the former insurgent stronghold of Anbar province. Provincial council member Sheik Efan Saadoun blamed the attack on a decision to replace police with Iraqi soldiers who are less familiar with the local surroundings. Car bombs, meanwhile, tore through two neighborhoods in restive cities north of Baghdad in separate attacks targeting a police captain and a provincial council member. One blew up in the northern city of Tuz Khormato about 50 yards (meters) from the house of Niazi Mohammed, a Turkomen member of the Salahuddin provincial council, according to police. City police chief Col. Hussein Ali said at least eight people were killed and 69 wounded in the blast, which left some 20 houses heavily damaged. A second car bomb was discovered about 100 yards (meters) from the blast site, but it did not explode, Ali said.