Tribesmen in the eastern Yemen province of Hadramawt have blown up an oil pipeline for the second time in two days, disrupting an important source of revenue for the impoverished state.
The attacks targeted a pipeline with a capacity of 120,000 barrels a day carrying crude from the Masila field, the most important in Yemen, local and tribal officials said.
Tuesday's blast, which caused a fireball that could be seen from several kilometers away, struck in the Wadi Urf area, while Monday's attack on the same pipeline was in the Sah area.
Tensions between tribes in Hadramawt and the government have been running high since early December, when an important chief was killed in a shooting at an army checkpoint, local media have reported.
The tribes have demanded the authorities pull their forces from the province, have attacked government and energy facilities and late last month overran an oil ministry building in Hadramawt.
The latest pipeline attacks were in response to fighting on Saturday between tribes and the army in which a young man was killed, local sources said. The tribes issued the army with an ultimatum to hand over the soldiers who killed him.
Yemen's oil income has been in decline for the past decade, but still represents around 70 percent of state revenues in the Arabian Peninsula country.
On Monday, Canada's Calvalley Petroleum said recent disruptions in Hadramawt had impacted on crude shipments rather than production capacity, but that some output had been shut down because storage tanks were full.
On Sunday Yemen said it had repaired another main pipeline in the north of the country after it was bombed by members of a different tribal group in December. Yemeni pipelines have also periodically been attacked by Islamist militants.
Poverty in Yemen could undermine the country's fragile political transition after its long-term leader Ali Abdullah Saleh was ousted in 2012.
Western governments fear a failure to accommodate the country's rival political, regional and tribal groups would lead to chaos that could be exploited by al-Qaida, which has a strong presence in remote areas.