Iraqi security officials say a car bomb blast outside a police academy in Baghdad has killed at least 18 recruits and officers and wounded more than 26 in the deadliest attack for weeks in the capital.

Police say a suicide bomber detonated his car as the recruits exited the compound's security barriers in northeastern Baghdad Sunday.

Hospital officials say all of the dead were either police officers or cadets. Iraqi police recruits have been attacked repeatedly as suicide bombers have infiltrated protection barriers and other checkpoints throughout the country.

The bombing breaks a short period of relative calm that accompanied an easing of a political crisis pitting Shi'ite Prime Minister Nouri al-Maliki against senior members of the Sunni-backed Iraqiya bloc. Late last month, a suicide bomber detonated an explosives-packed vehicle near a Shi'ite funeral procession in Baghdad, killing at least 31 people.

No one has claimed responsibility for Sunday's attack. Last week, Iraqi and U.S. officials said the Sunni Muslim extremist network al-Qaida – for whom suicide bombings are a favored tactic – remains a potent threat in Iraq.