Fire and smoke billow from the Norwegian-owned Front Altair tanker in the Gulf of Oman on June 13. (Photo by AFP/Getty Images)

(CNSNews.com) – Secretary of State Mike Pompeo on Thursday accused the Iranian regime of responsibility for attacks on two tankers near the Persian Gulf, and slapped down his Iranian counterpart for a tweet insinuating some sort of anti-Iran conspiracy behind the incident.

"It is the assessment of the United States government that the Islamic Republic of Iran is responsible for the attacks that occurred in the Gulf of Oman today," Pompeo said. "This assessment is based on intelligence, the weapons used, the level of expertise needed to execute the operation, recent similar Iranian attacks on shipping, and the fact that no proxy group operating in the area has the resources and proficiency to act with such a high degree of sophistication.”

He quoted Foreign Minister Javad Zarif as having “sardonically” tweeted, “Suspicious doesn’t begin to describe what likely transpired this morning.”

“Foreign Minister Zarif may think this is funny, but no one else in the world does,” Pompeo said.

Two tankers caught fire after explosions in the Gulf of Oman south of the Strait of Hormuz early on Thursday, and crews were forced to abandon ship. The ships were the Japanese-owned Kokuka Courageous, carrying a cargo of methanol, and the Norwegian-owned Front Altair, laden with naphtha.

Just a month ago, four tankers sustained damage in similar incidents, also in the Gulf of Oman but closer to the United Arab Emirates coast. The U.S. accused Iran of responsibility in that case, and the UAE told the U.N. Security Council a “state actor” was most likely behind those attacks. Iran denied responsibility.

Iranian Foreign Minister Javad Zarif. (Photo by Michael Gruber/Getty Images)

In his tweet Thursday, Zarif noted the timing of the latest attack on a ship associated with Japan – as Japanese Prime Minister Shinzo Abe was paying a closely-watched visit to Tehran, the first by a Japanese leader since the 1979 Islamic revolution.

“Reported attacks on Japan-related tankers occurred while [Abe] was meeting with Ayatollah [Ali Khamenei] for extensive and friendly talks,” he said. “Suspicious doesn't begin to describe what likely transpired this morning.”

Pompeo also pointed to the Japanese aspect, but with a different perspective.

He noted that Abe had urged the regime to de-escalate tensions and “enter into talks,” and that Khamenei had rejected the appeal.

“The supreme leader’s government then insulted Japan by attacking a Japanese oil tanker just outside of Iranian waters, threatening the lives of the entire crew, creating a maritime emergency,” Pompeo charged.

Iranian supreme leader Ayatollah Ali Khamenei meets with Japanese Prime Minister Shinzo Abe in Tehran on Thursday. (Photo: Office of the Supreme Leader)

‘I do not consider Trump as a person worth exchanging any message with’

As Pompeo mentioned in his statement, Khamenei on Thursday turned down Abe’s appeals for the regime to engage with the U.S.

A statement posted on the official website of the supreme leader said that Abe had relayed “a message from the president of the United States.”

“We do not doubt your sincerity and goodwill,” Khamenei told the Japanese visitor. “However, regarding what you mentioned about the president of the U.S., I do not consider [President] Trump as a person worth exchanging any message with and I have no answer for him, nor will I respond to him in the future.”

In his statement, Pompeo said Thursday’s attacks were the latest in a series which he blamed on Iran and its regional surrogates, all coming after Iran on April 22 threatened the flow of oil through the Strait of Hormuz. Some 30 percent of the world’s crude oil passes through the crucial waterway.

“It is now working to execute on that promise,” Pompeo said. He listed the incidents:

--In early May, the Islamic Revolutionary Guard Corps (IRGC) “attempted the covert deployment of modified dhows capable of launching missiles.”

--May 12: Four commercial ships are attacked near the Strait of Hormuz. The U.S. accuses Iran.

--May 14: Iranian surrogates use drones to attack key Saudi oil pipelines.

--May 19: A rocket lands near the U.S. Embassy in Baghdad.

--May 31: A car bomb in Afghanistan wounds four U.S. service members and kills four Afghan civilians. (The Taliban claimed responsibility; Iran has a long relationship with the Taliban. A Pentagon report last December said the IRGC Qods Force “provides weapons, explosives, training, financing, and political support to the Taliban to counter the U.S. and coalition military presence, combat [the local ISIS affiliate], and position itself as an arbiter for peace talks.”)

--June 12: Iranian-backed Houthis in Yemen fire a missile that strikes an airport terminal in southern Saudi Arabia, injuring 26 people.

“Taken as a whole, these unprovoked attacks present a clear threat to international peace and security, a blatant assault on the freedom of navigation, and an unacceptable campaign of escalating tension by Iran,” Pompeo said.

He said the Iranian regime “should meet diplomacy with diplomacy, not with terror, bloodshed, and extortion.”

“The United States will defend its forces, interests, and stand with our partners and allies to safeguard global commerce and regional stability,” he concluded.

“We call upon all nations threatened by Iran's provocative acts to join us in that endeavor.”