SANAA: 16 Shiite rebels and five soldiers were killed in clashes in northern Yemen on Friday, a day after 15 local aid workers were kidnapped, as fighting intensifies in the poor Arab country.

Rebels loyal to leader Abdul-Malik Al-Houthi attacked and damaged a government building in the northern province of Amran, a local government source said.

Rebels took Red Crescent doctors, nurses, officials and administrators from a refugee camp in the neighboring province of Saada on Thursday, Hassan Al-Manna, the province’s governor, said earlier.

The rebels have displaced around 17,000 families from their homes in the mountainous northern province of Saada over the past four days, Manna said, according to the Yemeni Defense Ministry website. Yemen on Thursday announced conditions for a cease-fire to end a government offensive against the rebels in the north of the mainly Sunni Muslim Arab country.

The rebels rejected the truce offer and denied holding any kidnapped civilians. Officials say the rebels want to restore a form of clerical rule prevalent in Yemen until the 1960s. The rebels say they are defending their villages against government oppression.

The government cease-fire conditions included a rebel withdrawal, the removal of their checkpoints and the clarification of the fate of kidnapped foreigners. They also required rebels to return captured military and civilian equipment, hand over those behind the June kidnapping of nine foreigners and refrain from intervening in local authority affairs.

Fighting between Yemeni troops backed by fighter aircraft and Shiite rebels killed and wounded dozens in the north of the country, local officials and rebels said on Wednesday.

Yemen, one of the poorest Arab countries, has been battling a Shiite rebellion, rising secessionist sentiment in the south and a wave of Al-Qaeda attacks. In July 2008, Yemeni President Ali Abdullah said four years of intermittent fighting against the rebels had ended and dialogue should replace combat. Despite attempts to start talks, sporadic fighting continued and intensified in recent weeks.

The rebels belong to the Shiite Zaydi sect and want Zaydi schools in their area. They also oppose the government’s alliance with the United States, and say they are defending their villages against government oppression.

Five waves of fierce fighting between the rebels and the military have left hundreds of soldiers and insurgents dead since 2004.

Authorities have accused the rebels of trying to reinstall the rule of imams, toppled by a republican revolution in northern Yemen in 1962.