Sana’a: At least 12 people were killed in northern Yemen overnight after tribesmen fought with a Shiite group which was trying to capture a mountain, tribal sources said on Monday.

The fighting in Yemen’s Omran province is the latest in a series of deadly confrontations in the north between Shiite Al Houthis and their Sunni rivals, who include local tribes and Salafist Islamists.

Months of intense sectarian fighting have cast a shadow over national reconciliation efforts in Yemen, a neighbour of major oil exporter Saudi Arabia and home to one of Al Qaida’s most active wings.

Eight Al Houthis and four members of the pro-Salafist Al Ahmar clan were killed late on Sunday after the Shi’ite rebels tried to seize the mountain, the local Sunni tribal sources said.

It was not immediately possible to independently confirm the clashes.

The two sides have been trying to implement a ceasefire agreed earlier this month, under which the Salafis have relocated to the Red Sea port city of Hudaida, more than 250km away.

While the ceasefire was largely holding across most of northern Yemen, clashes have continued in more remote areas in Omran, where fighters are trying to gain control of territory, the sources added.

The adjacent Sa’ada province is the base for a long-running Al Houthi uprising against the Yemeni government in Sana’a, which the rebels say discriminates against them.

The Sunni-Shiite conflict has compounded the challenges facing Yemen, a US ally and the poorest Arab country.

It is also struggling with a separatist movement in the south, where mainly Islamist militants took advantage of a popular uprising in 2011 to strengthen their hold on some areas.