SANAA, Aug 14 (Reuters) - Shi'ite rebels kidnapped 15 Yemeni aid workers on Friday and clashed with government forces in the north of the country, a government official said.
Followers of rebel leader Abdul-Malik al-Houthi took Red Crescent doctors, nurses, officials and administrators from a refugee camp, said Hassan al-Manna, governor of Saada province.
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 Defence Ministry website.
Friday's kidnappings came the day after Yemen issued the rebels with the terms of a ceasefire to end a government offensive against them in the north of the mainly Sunni Muslim Arab country.
The rebels rejected Thursday's 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 ceasefire 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.
Yemen, one of the poorest Arab countries, has been battling a Shi'ite rebellion, rising secessionist sentiment in the south and a wave of al Qaeda attacks.
Al Qaeda's wing in Yemen named a new leader this year and said it would expand the scope of its attacks to all Gulf Arab states, including top world oil exporter Saudi Arabia.
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 Shi'ite 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.
(Reporting by Mohammed Ghobari; Writing by Jason Benham; Editing by Jon Boyle)