Iran's Revolutionary Guards threatened to open "new fronts" and keep the Strait of Hormuz closed over Israel's offensive in Lebanon, state media reported on Monday.

Iran's Tasnim news agency said Tehran was suspending all exchanges with mediators in peace talks with the United States on Monday, blaming Israel's ongoing invasion of Lebanon.

"Given the continuing crimes of the Zionist regime (Israel) in Lebanon and considering that Lebanon was one of the preconditions for the ceasefire and that this ceasefire has now been violated on all fronts, including Lebanon, the Iranian negotiating team is suspending dialogues and exchange of texts through mediators," Tasnim reported.

The United States and Iran said Monday they had again traded strikes, straining an already fragile ceasefire as negotiations between the two sides have stalled.

Weeks of complicated talks marked by sharp rhetoric and occasional flare-ups of violence have not managed to reach a deal to end the war and reopen the Strait of Hormuz, which is essential to oil supplies.

Iran's chief negotiator warned the United States is not to be trusted Sunday, saying Tehran would not agree to any deal with Washington unless it fully secures Iranian rights.

U.S. President Donald Trump said he had secured guarantees from Iran that it would not develop nuclear weapons, as reports emerged he had sent a tougher peace proposal back to Tehran.

Any tweaks to the proposal could prolong even further an agreement to formally end the Middle East war and open the Strait of Hormuz maritime route after weeks of efforts to secure a deal despite fractious rhetoric and the occasional flare up of armed conflict.

The United States warned on Saturday it was "more than capable" of resuming war with Iran after President Donald Trump said any peace deal must adhere to his red lines, including Tehran never being able to develop nuclear weapons.

U.S. President Donald Trump on Friday said he was now making a "final" decision on whether or not to strike a peace deal with Iran.

U.S. President Donald Trump said any agreement with Iran would depend on securing a “good deal” for the United States as negotiations over Tehran’s nuclear program intensify alongside continued military tensions in the Gulf.

“A deal that wasn’t going to be good for us is the line,” Trump told Fox News in an interview set to air this weekend. “I negotiate. They negotiate. They’re very good negotiators.”

The United States and Iran have made good progress towards a ceasefire extension deal but President Donald Trump is not yet ready to approve it, U.S. Vice President JD Vance said Thursday.

U.S. and Iranian negotiators have reached an agreement on a 60-day memorandum of understanding to extend the ceasefire and launch negotiations on Iran's nuclear program, but U.S. President Donald Trump has yet to give it his final approval, two U.S. officials and a regional source involved in the mediation efforts told U.S. news portal Axios.