KARUIZAWA: Energy ministers from the Group of 20 major economies have shared concerns over attacks on tankers in the Gulf and will collaborate to maintain stability in the oil market, Japan's Industry Minister Hiroshige Seko said on Saturday.

Two tankers, one operated by a Japanese shipping company, were attacked on Thursday. The United States blamed Iran for the attacks, raising concerns about a confrontation and driving up oil prices.

"The most important thing was that we have shared an understanding among energy ministers that we need to work together to deal with the recent incidents from energy security point of view," Seko told reporters at a meeting of G20 energy and environment ministers being held this weekend in Karuizawa.

"Same thing happened at our bilateral meetings," he said, referring to talks with officials from several countries including Saudi Arabia and the United States.

Saudi Energy Minister Khalid al-Falih told Seko in their bilateral meeting that it took recent events, including a May 12 attack on four tankers off the United Arab Emirates, "very seriously."

The recent attacks were more harmful than physical damage to the ships as they affected global confidence in energy supply security, he said. "The Kingdom is committed to ensuring stability of global oil markets," he added.

Dan Brouillette, US deputy secretary of energy, also condemned the attacks.

"We stand firmly with Japanese and everyone else," he told a news conference on the sideline of the G20 ministerial meeting.

A G20 summit is to be held in Osaka on June 28-29.