A bomb blast killed three policemen and wounded a fourth on Saturday in the Yemeni capital of Sanaa, according to security sources.

A bomb blast killed three policemen and wounded a fourth on Saturday in the Yemeni capital of Sanaa, according to security sources.

The device was put in a plastic bag near a police check point in the north of the capital.

The deadly blast came after a period of relative calm in the Yemeni capital.

A manhunt has been launched for those behind the attack, the official added.

Yemen's politicians are currently taking part in a national dialogue aimed at paving the way for a new constitution and planned for February 2014 general elections.