Aden (Yemen), May 20 : Eight people were killed and at least 15 others wounded in clashes between tribal gunmen in Yemen's northeastern oil-rich province of Marib, a government official said. Ferocious clashes erupted on Thursday night and continued into Friday morning between gunmen from the Al Munif and Al Fahih tribes in the Al Wadi district of Marib, the local government official said on condition of anonymity on Friday. The clashes were caused by a dispute over land ownership between the two tribes, the source said, adding a ceasefire began to take effect on Friday night, Xinhua news agency reported. Despite the ceasefire, tensions remain high as both sides have deployed heavily armed reinforcements in different areas of Marib, according to the official. Marib province, which houses Yemen's most crucial oil and gas fields, is controlled by Yemen's internationally recognised government. In recent years, the province has been engulfed in intense conflicts between government forces and Houthi rebels. Yemen's civil war flared in late 2014 when the Houthi group seized control over much of the country's north and forced the internationally recognised government out of the capital Sanaa. /IANS