SANAA Aug 6 (Reuters) - Tribesmen shot down a Yemeni military helicopter on Tuesday as it fired rockets at gunmen suspected of involvement in blowing up oil pipelines in the centre of the country, witnesses said.
The government has been frustrated by repeated attacks on Yemen's main oil export pipeline, often carried out by disgruntled tribesmen seeking personal gain or trying to force authorities to release jailed relatives.
Witnesses said the helicopter pilot was killed when the helicopter came down in the central Maarib province.
"The helicopter was firing from a low altitude at armed tribesmen accused of blowing up the oil pipeline," one witness said. "The gunmen fired back with a machinegun and it crashed."
Defence Ministry officials could not immediately be reached for a comment.
Yemen, one of the most impoverished countries in the Arab World, is facing a host of challenges as it tries to restore state authority nearly two years after long-serving President Ali Abdullah Saleh was forced to step down in 2011, including a regular challenge to state authority by armed tribesmen.
The country of 25 million depends for between 60 and 70 percent of its state budget on oil revenues. The last pipeline attack, on Saturday, came less than a week after it was repaired following a similar bombing. (Reporting by Mohammed Ghobari, writing by Sami Aboudi; Editing by Jon Boyle)