"Three military brigades were deployed to Sarwah area in Marib province to protect the engineering team which was repairing the oil pipeline from Marib to the export terminal in Ras Esa area on the Red Sea coast which was bombed several times last year," the ministry said in a statement on its website.

Meanwhile, security officials and residents said the militants fired two mortar shells on the military forces upon their arrival to Sarwah early on Monday. They said the forces fired back, but no casualties were reported until now as the repairing operations were going on.

Several armed tribes and Islamic groups have frequently attacked crude export pipelines to force the government to meet their demands, which further deteriorates the fuel shortage in the Arab country since popular protests erupted against former president Ali Abdullah Saleh in January last year.

President Abd-Rabbu Mansour Hadi said recently that his country has lost more than two billion U.S. dollars due to repeated attacks on the oil export pipeline.

The pipeline had been attacked nine times over the past 11 months, leading to reduction of output of 125,000 barrels per day at Ras Issa terminal on the Red Sea.

The cash-stripped Yemeni government depends on oil exports for up to 70 percent of its budget.

Hadi, who replaced Saleh in February following one-year unrest, has promised to continue fighting terrorist groups and improve his country's economy during his two-year interim term.