Updated

Al Qaeda may be responsible for an attack on an oil pipeline in Yemen on Tuesday, a local security official said. But other anonymous government officials were quick to caution that other groups may be responsible.

Local officials told Reuters news that they suspected al Qaeda militants were responsible for blowing up a small oil pipeline in southern Yemen on Tuesday -- the same day the country launched a hunt for those responsible for a plot to mail bombs to the United States.

However, an official who spoke with the Associated Press on conditions of anonymity could not confirm that the militant group was responsible.

The pipeline in the province of Shabwa was operated by a South Korean firm, officials said, but declined to give further details. It was not clear if exports would be affected.

The blast on the pipeline taking crude oil to a maritime export terminal was caused by a timed device, a local security official told Reuters, adding that members of al Qaeda were believed to be behind the attack.

Over the past year, tribesmen have attacked pipelines, in several cases to protest civilian deaths in government airstrikes targeting the Al Qaeda group, the Associated Press reported. Gangs have also been suspected of sabotaging pipelines to extort money from government officials, the group reported, suggesting that these gangs may be responsible for the bombing.

Yemen launched a major operation on Tuesday to arrest a Saudi bomb maker accused of being behind a foiled bomb plot involving U.S.-bound parcels. Security forces were sent to the province of Maarib and also to Shabwa, where the targeted pipeline is located.

Al Qaeda has in the past threatened to target Yemen's oil and gas infrastructure, but such attacks have been relatively rare.

Disgruntled tribes have sporadically blown up pipelines to pressure the government.

Last month, a gunman believed to have links to Al Qaeda killed a Frenchman at Austrian oil and gas company OMV's site in Sanaa.

The Yemen wing of the global militant network, Al Qaeda in the Arabian Peninsula, has strongholds in Maarib and Shabwa, where oil and gas fields of international companies are located.

Militant attacks in Yemen could threaten its small but vital energy operations as well as having potential knock-on effects for the wider oil producing region if insurgents take advantage of the country's instability.

Yemen is a small oil producer in a region of export giants such as neighbor and top exporter Saudi Arabia, so interruption of its 300,000 barrels per day (bpd) output would have little impact on international energy markets.

But Yemen relies on oil revenues for 70-75 percent of public revenue and more than 90 percent of export earnings. Any interruption to that income would put pressure on the budget of an already desperately poor country that says it needs billions of dollars of economic aid.

News wires contributed to this report.