Yemen's military officials say they have killed at least 30 Houthi fighters in their strongholds in Sa'ada and Amran provinces in the mountainous north.

Troops killed 12 Houthis in clashes on Tuesday in Harf Sufyan district in Amran province, 70 kilometers (40 miles) north of Sana'a, the state-run Saba news agency quoted a commander as saying.

The commander said the other 18 fighters were killed in separate clashes in Sa'ada province, adding the army also targeted five cargoes of explosives bound for anti-government forces in the far north province.

The Yemeni government launched an all-out military offensive -- namely Operation Scorched Earth -- in August in a bid to quash the five-year-old uprising by Houthi Shias in the north.

They accuse the Sunni-dominated Sana'a government of neglect and discrimination against Shia Muslims, who make 30 percent of the country's population.

The clampdown coincides with mounting calls in the south for the restoration of its independence before the north and south unified in 1990.

On Wednesday, anti-government demonstrations entered a second day as thousands of people poured into the streets in the city of Daleh in protest to the economic and political marginalization of the south.

They called for the release of 15 southern activists, including two women, arrested during Tuesday's demonstrations in Aden which called for Arab support for the independence of the south.

The Socialist party, which ruled former South Yemen, said on its website that police resorted to violence to disperse demonstrators in Aden and booked around 200 protesters.

MRS/AKM