Five American troops have been killed in an Iraq rocket attack, according to Iraqi security officials. Three or more rockets hit an Iraqi base in Baghdad this morning where the troops were living as advisers, they say. The US military had earlier acknowledged five troops were killed but offered no details, the AP reports. The incident marks the single largest loss of life for American troops in Iraq since May 2009, when five were killed in a non-combat incident. According to AP's count, 4,459 American service members have died in Iraq. (More Iraq stories.)