A US drone attack killed at least five suspected al Qaeda militants in southern Yemen on Friday, and gunmen retaliated by blowing up a feed pipeline of an LNG terminal, forcing gas output to be stopped, officials and energy workers said.

The closure of the LNG terminal is expected to cut its super-cooled gas exports by about four cargoes, the operator said in a statement.

Gunmen on Friday night blew up the 38 inch gas pipeline that links Yemen's block 18 to the liquefied natural gas (LNG) terminal at Balhaf on the Gulf of Aden.

"Yemen LNG confirms the sabotage," Yemen LNG, which is run by France's Total, said in a statement late on Friday.

"Production has stopped but the loss of production is expected to be limited to four cargoes as the LNG plant was due to shutdown on April 15 for annual maintenance."

The $4.5 billion plant was also forced to close in October 2011 after its feed line was blown up by suspected Al Qaeda militants.

But the quick repair of the pipeline and the rescheduling of annual maintenance at the terminal to coincide with the repairs allowed Yemen LNG to deliver all the 106 LNG cargoes it agreed to sell last year.

The attacks on Yemen LNG's supplies follow a series of attacks on oil pipelines which have intensified the country's economic crisis since early 2011.-Reuters