At least 15 protesters and a policeman were wounded in fierce clashes marked the seventh straight day of tensions between government backers, police and demonstrators in Yemen's capital on Thursday, witnesses said.

Some 500 anti-government protesters, mostly students demanding the ousting of President Ali Abdullah Saleh, gathered inside Sanaa University and marched to the south gate of the campus, where they clashed with pro-regime supporters wielding daggers and batons, leaving at least 15 protesters injured.

Anti-riot policemen rushed to the scene in Al-Rubat Street to try to break up the clashes between the two rivals, one policeman was seriously wounded, a police officer told Xinhua on condition of anonymity.

A Xinhua correspondent said the armed government backers were still chasing down the protesters as both sides were throwing stones against each other while police fired warning shots to the air.

Another several hundreds of anti-government protesters took to the streets in provinces of Al-Bayda, Al-Hodayda, Taiz, Abyan and Aden, shouting slogans that call for the ouster of Saleh, according to a security source at the Interior Ministry.

Clashes were taking place between the demonstrators and the anti-riot policemen, there is no further reports of casualties yet.

Meanwhile, a group of clerics in Sanaa gathered in a conference to call for the formation of a national unity government between the ruling party and opposition coalition in order to save the country from chaos, a Xinhua reporter said.

The clerics, including influential figures such as Sheikh Abdulmajid al-Zindany, the head of Al-Eyman University and a prominent figure in the opposition Islah party, are demanding the rival factions to immediately form a transitional unity government to end the unrest in streets.

They said that the national unity government will solve the Yemeni political tension and that it would place Yemen in the same situation as Egypt and Tunisia, without suffering bloodshed.

Saleh, who has been in power for 33 years and is facing growing popular protests demanding him to step down, announced earlier this month to step down after his term expires in 2013 and promised not to hand power over to his son.

The opposition coalition agreed last week to a Saleh's political imitative and said they are ready to engage in a dialogue and form a national unity government that would save Yemeni people out of chaos, especial that one in two persons in Yemen own weapons.

Yemen, an impoverished Arab country, struggles to cement a fragile ceasefire deal with a Shiite rebellion in the north and to quell a growing separatist movement in the south while mounting resurgent al-Qaida regional group rampaging through the country's major cities.

Northern Shiite rebel commander Abdulmalik al-Houthi pledged in a statement posted on the internet Tuesday to order his armed groups to support the Yemeni people against Saleh if the revolution breaks out.