Iraqi officials say a wave of attacks across the country has killed at least 50 people and wounded more than 200 others in one of the deadliest days this year.

Most of the deaths Thursday came in Baghdad, where several bombs exploded including one in the city's mainly Shi'ite Karradah district that killed nine people and wounded 24 others.

Militants also stuck 10 other cities and towns with attacks on security patrols, a restaurant and a school.

The outbreak of violence follows a car bombing Sunday in Baghdad that killed at least 19 rectuirs outside a police academy.

Prior to that, the capital had seen weeks of relative calm accompanied by the easing of political tensions between Iraq's Shi'ite prime minister and senior members of a Sunni political bloc.