Yemeni military officials say thousands of troops, backed by tanks and warplanes, have launched a major offensive in a southern province to rout Al Qaeda militants from the area.

The officials say the operation in Hadramawt began at dawn on Wednesday, involving more than 10,000 troops, backed with tanks and artillery. Helicopter gunships and jet-fighters are providing air support.

They said the fighting was taking place in farmlands and that civilians have been instructed to stay indoors.

The officials spoke on condition of anonymity because they were not authorized to speak to the media.

The United States sees Al Qaeda in Yemen as among the world's most active branches of the terror network. Its fighters overran large swathes of southern Yemen in 2001 but they have been pushed back with U.S. help.