Tribal fighters sabotaged an oil pipeline early Tuesday in the eastern Yemeni province of Marib and cut the road between the region's gas fields and the capital, sources said.
The pipeline connecting Marib's oil fields to the Red Sea was an inferno, security officials said.
The fighters also severed the main road between Sanaa and Safer, disrupting tanker traffic and jeopardising gas supplies to the capital, tribal sources said.
The heavily armed tribes of Marib intended to pressure the government, the sources said, without defining their objective.
The sabotage attack comes as popular revolt against President Ali Abdullah Saleh's 32-year rule spreads across the country.
Security forces on Monday fired on protesters marching on the governor of Marib's headquarters. Seventeen demonstrators were injured, local officials said.
The governor, Naji Al-Zaidi, was stabbed in the neck when he attempted to calm the crowd, according to defence ministry website 26sep.net.
However, one protester said the governor was injured during a dispute between security forces and his own bodyguards, four of whom, according to 26sep.net, were also injured.
Yemen's tribes have in the past sabotaged oil pipelines in protest at central government policy.
Yemen, which is already battling secessionist unrest and a Shia sectarian rebellion, is the poorest country on the Arab peninsula. It is not a member of OPEC but produces some 300,000 barrels of crude oil per day.