Secretary of State Mike Pompeo blamed Iran for a “blatant assault” on two ships in the Gulf of Oman earlier Thursday and said the United States would defend itself and its allies against Iran’s actions in the region.

Speaking to reporters for four minutes and taking no questions, Pompeo offered no evidence of Iran’s involvement in the explosions aboard two oil tankers near the Strait of Hormuz. He said that the assessment of blame is based on intelligence, the type of weapons used and the level of expertise needed, and that no other Iranian-backed militia in the region has the resources or proficiency to pull off such a sophisticated operation.

Pompeo said the impetus behind the attacks was the administration’s “maximum-pressure campaign” of sanctions that U.S. officials say are designed to get Iran to negotiate over its nuclear program and support of militias in various neighboring countries. 

“Our policy remains an economic and diplomatic effort to bring Iran back to the negotiating table at the right time and encourage a comprehensive deal that addresses the broad range of threats,” Pompeo said.

“Iran should meet diplomacy with diplomacy, not with terror, bloodshed and extortion,” he said.

After a closed-door session of the Security Council, Jonathan Cohen, the U.S. ambassador to the United Nations, told reporters he expected more conversations in coming days on how to respond to the incident.

Secretary of State Mike Pompeo delivers remarks about Iran at the State Department on June 13, 2019. (Eric Baradat/AFP/Getty Images)

“The United States will continue its diplomatic and economic efforts to bring Iran to the negotiating table,” he said. “And Iran should meet with us diplomatically, not with terror, attacks on ships, infrastructure and diplomatic facilities.”

One year after President Trump withdrew the United States from the 2015 nuclear deal negotiated with Iran by his predecessor, tensions between the United States and Iran have escalated sharply. 

Pompeo ticked off some of the recent incidents against the United States and its allies, part of what he characterized as “40 years of unprovoked aggression against freedom-loving nations.”

Among them were attacks on four ships in the Gulf last month, the deployment of small dhows capable of launching missiles, a missile strike on an international airport in Saudi Arabia, and a car bomb in Afghanistan that wounded U.S. service members and killed four civilians.

“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,” he said.

Dennis Ross, a former diplomat with the Washington Institute for Near East Policy, noted that Pompeo did not mentioned the word military, while emphasizing diplomacy and the economic pressure campaign.

“On the one hand, we’re shining a spotlight on the Iranians, trying to make it clear they’re responsible in the hopes it will make them more cautious and less likely to do this,” he said. “It’s also an effort to get others to be responsive to the United States, when they see the U.S. emphasizing not a military response but a diplomatic response. The combination can mean more international support.”

But Ross said he expects the Iranians to continue denying any involvement in the tanker explosions.

“They’re already adopting in their own way maximum pressure on us, in response to our approach,” he said.

Thursday’s attack on a Japanese and a Norwegian tanker came as Japanese Prime Minister Shinzo Abe was in Tehran to ask that Iran de-escalate the situation and enter into negotiations with the United States.

“Iran’s supreme leader rejected Prime Minister Abe’s diplomacy today by saying he has no response to President Trump and will not answer,” Pompeo said. He called the attack on the Japanese tanker an insult on Japan itself.

He quoted Iranian Foreign Minister Mohammad Javad Zarif’s “sardonic” response to the tanker attacks: “Suspicious doesn’t begin to describe what likely transpired this morning.”

“Foreign Minister Zarif may think this is funny,” Pompeo said. “But no one else in the world does. Iran is lashing out because the regime wants our successful maximum-pressure campaign lifted. No economic sanctions tell the Islamic Republic to attack innocent civilians, disrupt global oil markets and engage in nuclear blackmail. The international community condemns Iran’s assault on the freedom of navigation and the targeting of innocent civilians.”