Iran, Tehran - Iran has laid out maps of regional power plants it threatened to target, in response to US President Donald Trump's ultimatum for it to reopen the vital Strait of Hormuz.

Iran's armed forces have since vowed to "completely" close the strait and target power plants in Israel, as well as in countries in the Gulf which Iran says support US bases in the area.

State media, including the judiciary's Mizan Online website, on Monday showed infographics of potential targets in Israel, including Orot Rabin and Rutenberg, Israel's two largest power plants.

Another infographic on Mehr news agency was titled "Say goodbye to electricity!" and showed possible targets in Saudi Arabia, the United Arab Emirates, Qatar, and Kuwait.

"In the event of the slightest attack on the electricity infrastructure of the Islamic republic, the entire region will be plunged into darkness," the graphic said.

Iran's powerful parliament speaker Mohammad Bagher Ghalibaf meanwhile vowed to "irreversibly" destroy vital infrastructure across the region if the US and Israel attacked its own.

Traffic through the Strait of Hormuz – through which 20% of the world's crude oil and liquefied natural gas normally passes – has been brought to a near-standstill since the start of the war.

Iranian forces have attacked multiple vessels, saying they failed to heed "warnings" against transiting the waterway.

In recent days, Iran has allowed some vessels from countries it considers friendly to pass, while warning it would block ships from countries it says have joined the "aggression" against it.