BAGHDAD: A series of attacks in Baghdad and north Iraq left four policemen dead and a dozen people wounded on Saturday, in the latest in a months-long surge in nationwide bloodshed.

The spike in violence, which has left more than 5,600 people dead so far this year, has forced Iraq to appeal for international help to combat militancy with just months to go before its first general election in four years.

Saturday's violence targeted police in the capital and the main northern city of Mosul.

In Baghdad, two separate bombings targeting police patrols killed three policemen and wounded 11 other people, security and medical officials said.

And in Mosul, militants opened fire on a police checkpoint, killing one policeman and wounding another.

The unrest is the latest in a protracted surge in attacks that has pushed violence to its highest level since 2008, when Iraq was recovering from the worst of its Sunni-Shiite sectarian war.

Prime Minister Nuri al-Maliki has called for Washington's help in the form of greater intelligence sharing and the timely delivery of new weapons systems in an effort to curb the bloodshed.