Iran "considers crossing the red lines in Lebanon and Gaza to mean direct war."
President Donald Trump announced "major combat operations" against Iran on Feb. 28, with massive joint U.S.-Israeli strikes targeting military, government and infrastructure sites.
Following the announcement of a two-week ceasefire, initial U.S.-Iran talks in Pakistan in April failed to reach a peace deal.
Trump later announced the open-ended extension of the ceasefire and the continuation of a U.S. blockade until negotiations are concluded "one way or the other."
Iran is stopping "dialogue and exchange of texts through mediation" due to Israel's strikes on Lebanon, Iran's semi-official news agency, Tasnim, reported.
Iran is also blocking the Strait of Hormuz, Tasnim reported.
Secretary of State Marco Rubio spoke with Lebanese President Joseph Aoun and Israeli Prime Minister Benjamin Netanyahu regarding ongoing negotiations between the two countries, a U.S. official told ABC News, and as Israel expanded its offensive against the Iran-backed Hezbollah militia in southern Lebanon.
The U.S., the official said, proposed that Israel would refrain from escalation in the Lebanese capital Beirut in exchange for Hezbollah's halt of all attacks on Israel. That step, the official said, "would create space for gradual de-escalation and an effective cessation of hostilities."
Aoun "tried to advance this proposal and secure an agreement," the U.S. official said, but was stymied by Lebanese Parliament Speaker Nabih Berri -- the head of the Shiite Amal Movement and a longtime political ally of Hezbollah.
The official described Berri's response as "evasive and disappointing," and "placed the burden on Israel to stop shooting first."
"Hezbollah is following Tehran's lead. It clearly has no interest in the welfare of the Lebanese people. Iran wants to prolong the conflict in Lebanon so it can claim credit for 'saving the day,'" the U.S. official said.
"The United States does not expect Israel to absorb ongoing attacks on its civilians by a terrorist organization. The fastest way to de-escalate and protect civilians on all sides is for Hezbollah to stop firing immediately," the official added.
The Islamic Revolutionary Guard Corps said on Monday that it launched a retaliatory attack on an unnamed air base following U.S. strikes on the Iranian island of Sirik in the Hormozgan region, which sits along the Strait of Hormuz.
"Following the aggression of the U.S. military against a telecommunications tower on Sirik Island, located in Hormozgan Province, an hour ago, IRGC Aerospace Force fighters targeted the air base from which the aggression originated, and the predicted targets were destroyed," the IRGC said in a statement carried by the semi-official Fars News Agency.
"If the aggression is repeated, the response will be completely different, and the responsibility lies with the aggressor and child-killing American regime," the IRGC said.
