UNITED NATIONS (Reuters) - The United States on Thursday called attacks on commercial shipping “unacceptable” and told the U.N. Security Council that the latest assaults on two oil tankers in the Gulf of Oman that left one ablaze and both adrift “raise very serious concerns.”

U.N. Secretary-General Antonio Guterres attends a session of the St. Petersburg International Economic Forum (SPIEF), Russia June 7, 2019. REUTERS/Maxim Shemetov

Council diplomats said the United States told them it planned to raise the issue of “safety and freedom of navigation” in the Gulf during a closed-door meeting of the Security Council later on Thursday.

“It’s unacceptable for any party to attack commercial shipping and today’s attacks on ships in the Gulf of Oman raise very serious concerns,” acting U.S. Ambassador to the U.N. Jonathan Cohen told a council meeting on U.N. and Arab League cooperation on Thursday morning.

“The U.S. government is providing assistance and will continue to assess the situation,” he said.

U.N. Secretary-General Antonio Guterres warned at the meeting that the world cannot afford “a major confrontation in the Gulf region.”

“I strongly condemn any attack against civilian vessels. Facts must be established and responsibilities clarified,” he said.

The attacks were the second in a month near the Strait of Hormuz, a major strategic waterway for world oil supplies.

The United States and Saudi Arabia blamed Iran for last month’s attacks using limpet mines on four tankers off the coast of the United Arab Emirates, a charge Tehran denies.

Arab League Secretary-General Ahmed Aboul Gheit called on the Security Council to act against those responsible to maintain security in the Gulf.

“Some parties in the region are trying to instigate fires in the region and we must be aware of that,” he told the 15-member council, without specifically naming anyone.

Kuwait’s Foreign Minister Sheikh Sabah Khaled al-Sabah described the tanker attacks as a threat to international peace and security.

“This is the most recent event in a series of acts of sabotage that are threatening the security of maritime corridors as well as threatening energy security of the world,” he said.