Iran live updates: US blockade of Iran's Strait of Hormuz ports to begin Monday

Iranian foreign ministry spokesman Esmaeil Baqaei said that Iran has been engaging in talks with Oman on examining "a procedure for the safe passage of vessels through the Strait of Hormuz."

Baqaei said the talks with Oman have been held at the level of deputy foreign ministers.

"We think these talks will continue until coming to a conclusion," he added.

Referring to President Donald Trump's deadline threat, Baqaei said Iranians will not be "subjugated" by deadlines in defending their country.

Trump threatened to target Iran's power plants and bridges unless the regime opens the Strait of Hormuz by Tuesday night.

Asked about reports of a draft proposal that includes a 45-day ceasefire and reopening of the Strait of Hormuz, a White House official told ABC News on Monday, "This is one of many ideas, and POTUS has not signed off on it. Operation Epic Fury continues. President Trump will speak more at 1 p.m."

The Associated Press reported on Monday that the U.S. and Iran had both received a draft proposal calling for a 45-day ceasefire and the reopening of the Strait of Hormuz to facilitate subsequent full peace talks. ABC News has not confirmed the reported plan.

Iran will not accept a ceasefire without "suitable guarantees," a Pakistani security official told ABC News on Monday.

"Any process for a ceasefire without suitable guarantees and assurances would be unacceptable to Iran," the official said, responding to reports that mediators are pushing for a ceasefire to halt the U.S.-Israel war against Iran.

Iranian Foreign Ministry spokesperson Esmaeil Baghaei said on Monday that a 15-point peace plan proposed by the U.S. to end the current conflict is unacceptable to Tehran.

Answering a question from the state-run news agency IRNA about reports of a new ceasefire plan during his weekly presser, Baghaei said, "A few days ago, they put forward proposals through intermediaries, and the 15-point U.S. plan was reflected through Pakistan and some other friendly countries."

"Right then we stated that such proposals are both extremely ambitious, unusual and illogical and not acceptable to us in any way," he said.

"Regardless of that proposal, we prepared the set of demands that we had and have based on our own interests and our own considerations," Baghaei said.