Energy and environment ministers from the Group of 20 major economies voiced concerns over disruptions in fuel supplies on Saturday following attacks on oil tankers in the Middle East.

The ministers began a two-day meeting in the resort town of Karuizawa in central Japan after Thursday's attacks heightened tensions in the region and sent crude oil prices surging.

"It is vital for the international community to respond collaboratively to such incidents from the perspective of ensuring global energy security," Japanese industry minister Hiroshige Seko, who is co-chairing the meeting, told participants.

"The G-20 shared the view that it is important to work together for the stability of the energy market," he later told reporters.

The United States has blamed Iran for the attacks on the two tankers, one of which was operated by a Tokyo-based company, an accusation Iran vehemently denies. The attacks occurred near the Strait of Hormuz, a strategically important corridor through which a third of all oil traded by sea passes.

In bilateral talks on the sidelines of the G-20 meeting, Seko told U.S. Deputy Energy Secretary Dan Brouillette he is "extremely concerned" by the incident, which took place as Japanese Prime Minister Shinzo Abe was visiting Tehran. Abe was hoping to help ease growing tensions between Iran and the United States over their row stemming from a nuclear deal that Iran reached with world powers in 2015.

"I recognize your concerns about the activities in the Strait of Hormuz. I will go back to Washington. I will be briefed on some of the intelligence matters, and I promise to call you to let you know what I learn," Brouillette said in their meeting, the start of which was open to the media.

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Also on the agenda is ways to utilize clean energy sources such as hydrogen, as well as efforts to reduce plastic waste in the ocean.

About 300 million tons of plastic waste is produced every year, of which 8 million tons ends up in the world's oceans, according to the U.N. Environment Program.

Japan drew criticism last year for refusing to endorse a Group of Seven statement setting a target for plastic litter reduction. The United States also did not sign the document.

Playing catch up, Japan is now aiming to garner support for a pledge to stop plastic waste from going into the ocean by 2050 at a G-20 leaders' meeting later this month in Osaka, western Japan.

The issue "is a global problem that needs to be addressed by both the public and private sectors," Seko said, adding that Japan will play its part by aiming to make businesses charge for disposable shopping bags by next April.

The G-20 consists of Argentina, Australia, Brazil, Britain, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United States and the European Union.