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."
When asked about Iran's decision to cease communications with the U.S., President Donald Trump told CNBC, "I really don't care. I couldn’t care less."
The president also reportedly told CNBC that he is "going to ask" Israeli Prime Minister Benjamin Netanyahu "what’s going on with Lebanon." This comes after Netanyahu called for strikes in Beirut to resume.
-ABC News’ Emily Chang and Michelle Stoddart
President Donald Trump reacted to Monday morning's news that Iran was stopping communications with the U.S. for negotiations for a peace deal, saying in a phone interview that Iran hadn't informed the U.S.
"It's an appropriate thing to say, because they're better negotiators than they are fighters. But they haven't informed us of that," Trump said when asked about Iran's decision to cease messaging, according to NBC News.
The president did indicate that the U.S. would not resume hostility but would go through with the blockade and "go silent" on Iran.
"It doesn't mean we're going to go and start dropping bombs all over there. We'll just go silent. We'll keep the blockade. Blockade is a piece of steel," Trump said, according to a post by the NBC reporter.
The Islamic Revolutionary Guard Corps said Iran "considers crossing the red lines in Lebanon and Gaza to mean direct war and the imposition of costs on its own national security and Islamic resistance."
In response, the IRGC said, Iran "resolves to carry out defensive operations by taking meaning-breaking actions, opening new fronts, and in addition, maintaining the Strait of Hormuz equation."
The Israeli military has warned residents of the southern suburbs of Beirut, Lebanon, to flee their homes amid potential impending strikes.
The Israeli military said it will target locations in the suburb of Dahiyeh if Hezbollah “continues launching rockets towards Israeli cities and towns.”
Israeli Prime Minister Benjamin Netanyahu earlier instructed the military to strike “terrorist targets" in Dahiyeh.