Iran threatened to close the Strait of Hormuz, according to state broadcaster Press TV on Wednesday, citing an unknown Iranian source.
According to the source, Iran would reopen the strait only under its own arrangements, "as per the Islamabad Memorandum of Understanding (MoU)."
The source added that Iran would "strike at least twice the number of targets hit" in response to any strikes by the United States.
"The developments of the past 48 hours show Iran won't back down from managing the Hormuz," the source noted.
"Any threat will receive a powerful response," the source told Press TV, noting that the regime "does not distinguish between the United States and its partners in the region."
The source also responded directly to threats made by US President Donald Trump against Iran, saying he "will gain nothing" from making such threats.
"He (Trump) will certainly lose both the Strait of Hormuz and the negotiations over a final agreement," said the source. "The choice is now his."
Eight members of the Iranian army were killed in US attacks on southern parts of Iran early on Wednesday, state media reported.
The victims belonged to the air force and navy and died due to strikes in Bandar Abbas and Bushehr, it added.
Trump: US will 'probably' strike Iran tonight
Trump said earlier on Wednesday that he would "probably hit Iran tonight" during a press conference in Ankara, Turkey, following the NATO summit.
"I'll give a little warning," said Trump. "We're going to hit them hard tonight."
Trump added that the US has "a score to settle" with Iran due to the regime "killing soldiers, killing people for 47 years."
He noted that the US may reimpose the blockade on the Strait of Hormuz, saying "everyone will be able to cross outside of them [Iran]."
"They might try to throw some mines, which will be hard because we destroyed their boats," he added.