President Donald Trump said Thursday that the United States is under no pressure to end the war with Iran, but "the clock is ticking" for Tehran, as a third aircraft carrier arrived in the Middle East.

Iranian media reported blasts over the capital Tehran, a first since an increasingly tenuous cease-fire in the Middle East war came into effect two weeks ago. It was not clear what caused the blasts.

Prospective peace talks in Pakistan were hanging in the balance, meanwhile, with no sign of a return to diplomacy to end a standoff in the Strait of Hormuz.

Since Trump indefinitely extended a cease-fire in the Middle East war, the U.S. and Iran have shifted their focus to Hormuz, a blockaded waterway through which a fifth of oil and liquefied natural gas exports ordinarily flow.

"I have all the time in the World, but Iran doesn't," Trump said on social media. "The clock is ticking!"

He added that Iran's military was destroyed and "their leaders are no longer with us, the Blockade is airtight and strong and, from there, it only gets worse."

Trump had earlier ordered the U.S. Navy to destroy any Iranian boat caught laying mines in Hormuz, which Iran has blockaded since the start of the war that spread across the region following a massive U.S.-Israeli attack.

'Shoot and kill'

The USS George H.W. Bush aircraft carrier has arrived in the Middle East, the U.S. military said Thursday, bringing the number of the massive American warships operating in the region to three.

A second carrier was operating in the Red Sea on Thursday, while a third is also in the region, according to social media posts by CENTCOM.

Iran's state news agency IRNA said the "sound of air defense firing" was heard in western Tehran, while the Mehr news agency reported that air defense systems were activated in several parts of the capital to counter "hostile targets."

Earlier, a U.S. fleet had boarded a vessel in the Indian Ocean that was allegedly transporting oil from Iran, and a senior Iranian official said Tehran had banked its first proceeds from the tolls it exacts on shipping through the strait.

Trump had said he "ordered the United States Navy to shoot and kill any boat, small boats though they may be... that is putting mines in the waters of the Strait of Hormuz."

Israel's Defense Minister Israel Katz, meanwhile, said Tel Aviv is prepared to resume the war and is awaiting approval from the U.S., warning Tehran could be pushed "back to the Stone Age."

Iran has vowed it would keep the strait closed to all but a trickle of approved vessels for as long as the U.S. Navy blockades its ports, brushing off demands from Trump to both reopen Hormuz and surrender its enriched uranium.

The U.S. responded to Iran's action by imposing its own blockade of Iranian ports, and on Thursday, the Pentagon announced that U.S. forces had "carried out a maritime interdiction and right-of-visit boarding of the sanctioned stateless vessel M/T Majestic X transporting oil from Iran, in the Indian Ocean."

'Not possible'

Deputy parliament speaker Hamidreza Hajibabaei said Iran received its first revenue from tolls it is imposing on ships seeking to cross Hormuz.

Analysts said Tehran believes its blockade gives it sufficient economic leverage to force Washington to back down on its main demands in peace talks.

Responding to remarks from Trump suggesting that Iranian leadership was "seriously fractured", Iran's president, parliament speaker and chief justice all posted a nearly identical message on social media on Thursday.

"One God, one nation, one leader, and one path; that path being the path to the victory of our dearer-than-life Iran," they all said.

Peace talks?

On Wednesday, Trump told the New York Post that talks could resume in Pakistan within two to three days, though no delegations were presently headed to Islamabad.

In the Pakistani capital, blanket security remained in place for the fourth straight day in anticipation of possible talks.

On Thursday, Trump ​said a deal with ⁠Iran ⁠would only be made when it ⁠is "appropriate ​and ​good" ⁠for ‌the ‌U.S.

Iran's Revolutionary Guards on Wednesday said they forced two ships onto the Iranian shore from the Strait of Hormuz.

The U.S. military's Central Command said its forces had so far "redirected 33 vessels since the start of the blockade against Iran."