Special to WorldTribune.com

CAIRO — Anti-government tribes have attacked a Western-operated oil facility in Yemen.

Officials said tribal fighters killed at least two soldiers in an attack on oil installations operated by Norway’s DNO in the southeastern province of Hadramaut.

The officials said the Jan. 11 attack came after the tribes warned DNO to stop operations amid anti-government protests.

The tribes have been attacking Yemeni energy assets in wake of the Army killing of a tribal chief in December 2013.

A week before the Jan. 11 strike, tribal fighters bombed a major oil pipeline to the Gulf of Aden.

Officials said the attacks on energy facilities have cost Yemen $4.75 billion between March 2011 and March 2013. They said the tribal attacks also reflected a growing secessionist movement in southern Yemen.

  Attacks on oil facilities have cost Yemen $4.75 billion in two years, Gulf of Aden, Hadramaut province, Norway’s DNO