A CZECH doctor has been freed several hours after being kidnapped by gunmen in the Yemeni capital Sanaa.

The doctor was walking to work at a private hospital when the armed assailants blocked her way with their car and seized her. She was the third foreigner to be snatched this month.

Security sources said the kidnappers later freed the woman unharmed, leaving her on a main road east of the capital. The reasons for the kidnapping and the release were not immediately clear.

The incident highlighted the increasing breakdown of security in the US-allied country, which is struggling to restore state authority weakened since mass unrest in 2011 that forced long-serving President Ali Abdullah Saleh to step down.

The kidnapping followed the abduction of a British oil worker by unidentified gunmen and a German seized by Yemeni tribesman to press for the release of their jailed relatives.

An intelligence officer, Colonel Ahmed Hashem, was shot dead on Saturday by suspected al Qaeda militants.