Aden: Unknown assailants have shot dead a Yemeni policeman and wounded four others in the country's restive south, a security official said on Wednesday, the fourth such attack in less than a week.

"The gunmen opened fire on a police checkpoint killing one policeman and wounding four others," late on Tuesday in the city of Ataq, the capital of Shabwa province, an Al Qaida stronghold, the official said.

On Sunday, gunmen killed a senior police official in the southeastern province of Hadramawt while the following day unknown assailants shot and wounded a police chief travelling between Aden and the nearby province of Lahij.

Bombs

Two other policemen were wounded on Saturday when roadside bombs planted in their camp exploded.

Attacks on Yemen's security forces, which officials attribute to Al Qaida, have escalated since newly-elected President Abd Rabbo Mansour Hadi pledged to eradicate extremism and militancy in the country's lawless south and east during his February 25 inauguration speech.

On Sunday, a massive assault on a Yemeni military base in Abyan province blamed on Al Qaida extremists killed 185 soldiers.