Gas exports from Yemen's Balhaf terminal on the Gulf of Aden were suspended on Saturday after a rocket attack blew up a pipeline just to the north, an engineer told AFP.
"The pumping of liquefied natural gas from the Balhaf terminal was stopped because of an explosion on one of its main pipelines," the engineer working at the site said.
"The pipeline was badly damaged, resulting in halting production," he said, adding that the pipeline was still on fire.
"We have not succeeded in containing the fire because the hole caused by the explosion is very big," he said, adding that fixing the pipeline "could take weeks."
A Shabwa provincial official told AFP earlier that overnight, saboteurs struck the pipeline in Al-Hahina district, just two kilomtres (a little over a mile) from the Balhaf terminal, disrupting its operations.
"Following the attack, operations were halted in several parts of the terminal," the official said asking not to be identified.
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Huge columns of flame and plumes of smoke were visible from as far as 25 kilometres (15 miles) away, witnesses told AFP.
There was no immediate claim for the attack but the provincial official said he thought it was likely to have been an Al-Qaeda attack carried out in retaliation for apparent US air strikes in Shabwa on Friday that killed seven Al-Qaeda militants, including a son of US-born cleric Anwar al-Awlaqi.
"I think it is a response to the air strikes," the official said.
The 320 kilometre (200 mile) gas pipeline links fields in Marib province further north with Balhaf in Shabwa.
Both provinces are strongholds of Al-Qaeda.
Yemen began exports of liquefied natural gas from the terminal in November 2009.
The impoverished nation had at the beginning of this year 478.5 billion cubic metres (around 17 trillion cubic feet) of proven reserves of natural gas, according to estimates.