Following a wave of U.S. strikes on Iranian targets on Sunday, Iranian Deputy Foreign Minister Kazem Gharibabadi released a statement, saying, "No action against Iran should go unanswered."

A spokesperson for the foreign minister also called the U.S and Israel's attacks "the continuation of a blatant and unprovoked act of aggression."

Addressing Iran's strikes on American assets in the Middle East, the spokesperson said, "Iran’s strikes on U.S. military bases and assets stationed in the southern Persian Gulf constitute a legitimate and lawful exercise of its inherent right to self-defense under international law."

The U.S. conducted a new round of strikes on Iranian targets on Sunday, a U.S. official told ABC News.

The targets included Iranian air defense systems and IRGC small boats around the Strait of Hormuz, the official said.

The strikes were intended to degrade Iran’s ability to target commercial shipping, according to the official, who said no U.S. troops were wounded in the attacks.

-ABC News' Steve Beynon

United Nations Secretary-General Antonio Guterres said he's “deeply concerned" by the increasing attacks in Iran and warned of "catastrophic consequences" globally should parties return to "full-scale hostilities."

"I am deeply concerned by the serious escalation & renewed military confrontations in the Gulf, including the Iranian attacks on ships in the Strait of Hormuz, the attacks by the US on Iran, and the attacks by Iran on targets in the neighboring countries," Guterres wrote in a post on X Sunday. "These attacks must all stop."

"A return to full-scale hostilities would have catastrophic consequences – for the peoples of the region, for international peace & security & for the global economy. I urge Iran & the US to urgently resume negotiations & to address outstanding issues through diplomacy," Guterres further wrote.

-ABC News Claire Bower

Several Gulf states and Pakistan responded to Iranian strikes on Saturday night and Sunday with strongly worded statements.

Qatar’s Foreign Ministry called the attacks “a blatant violation of the sovereignty and territorial integrity of the targeted countries, and a flagrant breach of international law, the Charter of the United Nations, and the principles of good neighborliness.”

In a statement posted on X, the ministry said it is holding Iran legally responsible for the strikes and their fallout.

Oman’s Foreign Ministry said in a statement on X that it summoned the Iranian ambassador to protest the strikes, expressing “dismay at these irresponsible acts.”

Pakistan's foreign ministry also voiced “deep concern” over the escalation in regional tensions and urged “all sides to exercise restraint, take immediate steps towards de-escalation and uphold respective commitments under the Islamabad Memorandum of Understanding (MoU).”

Saudi Arabia’s Ministry of Foreign Affairs condemned what it called Iran’s “continued destabilizing behavior that undermines the security and stability of the region, and its violation of the principles of international law.”

-ABC News' Claire Bower