US troops detained the son of Iraq's top Shi'ite politician Friday as he returned to the country from Iran but released him nearly 12 hours later, Shi'ite officials said. The US ambassador apologized for the arrest. Amar al-Hakim, son of political leader Abdul-Aziz al-Hakim, was taken into custody at the Zirbatyah crossing point and was transferred to a US facility in Kut, according to the elder al-Hakim's secretary, Jamal al-Sagheer. Al-Sagheer said the younger al-Hakim's security guards were also detained. Later, al-Sagheer said Amar al-Hakim was freed about 8 p.m. but his bodyguards remained in custody.