Yemen security officials say they have launched a major offensive in the southern part of the country to capture a group of suspected Islamic extremists.

Yemeni forces, supported by helicopters and heavy equipment, are sweeping through a mountainous region where about 80 members of the Yemeni Islamic Jihad group are believed to be hiding.

Officials say at least three suspects have already been taken into custody. Authorities are hoping the rest of the militants will surrender to avoid bloodshed.

Tuesday's crackdown follows an ambush Saturday by suspected militants on an army medical convoy that left several Yemenis injured.

Yemen, previously a safe haven for extremists, has been clamping down on suspected terrorists since the September 11, 2001, terrorist attacks on the United States.