Thousands of protesters demanding immediate ousting of Yemeni President Ali Abdullah Saleh shut down three government offices by force in the southern city port of Aden on Saturday evening, a local security official said.

"With shouting anti-government slogans, the crowd moved from their sit-in epicenter in Crater district to Seara area in downtown Aden, where they surrounded the provincial offices of Civil Service, Social Affairs and Work as well as the Local Council," the official told Xinhua on condition of anonymity.

He said the crowds then put heavy chains around the offices and replaced the original lock of the offices' main gates.

"The police forces stood aside and did not intervene in as the protesters then peacefully returned to their sit-in area," said the official.

Meanwhile, the same official said that the police arrested three people suspected of hurling a hand grenade bomb earlier the day on the office of Aden governor. No casualty was reported, he added.

Aden has witnessed almost daily civil disobedience to press for the end of Saleh's 33-year rule.

Three-month-long street protests and political deadlock between Saleh's ruling party and the opposition have almost brought the country on the verge of security and economic collapse.