The Yemeni president’s own tribe has called on him to step down after a deadly crackdown on protesters, robbing the embattled US-backed leader of vital support in a society dominated by blood ties.

Yemen's embattled president has failed to pacify protesters with plans to draw up a new constitution.

The Yemeni government escalated its efforts to stop mass protests calling for the president’s ousting, with soldiers firing rubber bullets and tear gas at students camped at a university in the capital in a raid that left at least 98 people wounded, officials said.