Despite promises of a truce, security forces in Yemen launched a night-time attack on a protest camp in the capital Sanaa on Saturday.
The AFP news agency reported that up to 5 people were killed as thousands of people were dispersed from around a street dubbed “Change Square”.
The overnight assault came following the deaths of 18 people, killed during violence at a large protest after Friday prayers.
The demonstration began hours after President Ali Abdullah Saleh returned from hospital in Saudi Arabia following an assassination attempt three months ago.
A statement from the Yemeni leader on state TV promised he was holding out an olive branch to pro-democracy demonstrators.
Meanwhile the US State Department urged Saleh to relinquish power and allow the country to “move on”.