The police forces opened fire to disperse an anti-government march of thousands of protesters in Yemen's western province of Al-Hodayda on Tuesday, injuring more than 20 protesters, witnesses said.

The police used live bullets and tear gas to put down the march demanding an immediate end to the 33-year rule of embattled President Ali Abdulla Saleh, one eyewitness told Xinhua.

More than 20 protesters were shot wounded. They were rushed to hospitals as several of them were in critical conditions, according to doctors.

The police late on Monday stormed a student anti-government sit- in inside the campus of Al-Hodayda University, injuring at least ten students.

The students demanded the postponement of classes in the university "until the regime of President Ali Abdullah Saleh falls, " the witnesses said.

Leaders of the opposition and youth-led protesters said on Tuesday they are considering to escalate their peaceful protests through marching forward all government ministries and presidential palaces in major cites to force Saleh's immediate ouster, two sources familiar with situation told Xinhua.

They said the escalation will take place based on the fruit of the consultative meeting of the foreign ministers of the Gulf Cooperation Council (GCC) in the Saudi Arabia capital of Riyadh on Tuesday.

Political stalemate in Yemen dominated the agenda of the six- nation GCC meeting.

On Sunday, the opposition gave President Saleh two days to sign the Gulf-brokered initiative for power transition, otherwise it would leave Saleh to face "the people's choice."

Yemen's security situation aggravated by the ongoing street protests since mid February, which repeatedly demanded of an immediate end to the rule of Saleh.