Too early to determine who blew up oil pipeline in Yemen: Lee

President Lee Myung-bak said Wednesday it is too early to determine who blew up a South Korean-run oil pipeline in Yemen amid reports of al-Qaida's suspected involvement, Yonhap news agency reported.

But Lee stressed the incident won't affect next week's summit of the Group of 20 nations.

The explosion came days after intercepted parcel bombs bound for the U.S. were traced to Yemen, raising concern about terrorism risks ahead of the Nov. 11-12 summit of the Group of 20 major nations in Seoul.

South Korean police have been on high anti-terror alert in the run-up to the summit.

Foreign news reports have said that al-Qaida militants are suspected in Tuesday's explosion at the underground pipeline in an oil field in Yemen's southern province of Shabwa, which is run by South Korea's state-run Korea National Oil Corp. (KNOC).

But reports also said that other anti-government insurgents are active in the region. Tribesmen have attacked pipelines in the past in protest against the government, and gangs have also attacked such facilities to extort money from the government.

No casualties have been reported in the explosion.

A large amount of oil is believed to have leaked from the pipeline following the explosion, but it is uncertain how much, a foreign ministry official said. The extent of the damage to the pipeline is also unclear because the facility is buried underground, he added.

Leaked oil later caught fire spontaneously due apparently to high temperatures there, he said.

What appeared to be explosive debris was found at the scene, the official said.

"For now, it is difficult to characterize the incident or who is behind it," he said. Still, he said that the ministry has alerted diplomatic missions in countries considered vulnerable to terrorist attacks to pay extra caution.

South Korea's embassy in Yemen has formed a task force to deal with the aftermath of the incident, he said.

The remaining oil in the pipeline has since been sucked back into a storage tank, and no more oil is leaking, another ministry official said.

The KNOC has been developing oil fields at four sites in Yemen since 2007.

The damaged pipeline belongs to a small oil field in which the KNOC acquired a 50 percent stake in 2008. The field has produced about 100 barrels a day.