Witnesses and medical staff said at least 30 people were also injured when Saleh's Republican Guards shelled some districts in Yemen's third largest city, a hotbed of anti-Saleh protests, and in clashes some 200 km south of Sanaa.

Opposition tribal fighters, using automatic rifles and shoulder-held rocket launchers, killed two soldiers and wounded seven, according to a Defense Ministry statement.

Residents said it was some of the most intense shelling since an uprising demanding that Saleh end his 33 years in office began in February.

Martin Nesirky, spokesman for UN Secretary-General Ban Ki-moon, said Benomar would report back to Ban, who is to inform the UN Security Council about the implementation of a resolution adopted last month that called on Saleh to accept a Gulf-brokered plan under which he would step down.