President Trump issued his latest threat in the war with Iran, vowing on Wednesday to impose “tremendous economic consequences” on countries that do business with Iran.

Mr. Trump did not specify in his social media post what actions he would take, and the White House did not immediately respond to questions on the matter. Treasury Secretary Scott Bessent warned last week of “never before seen” measures to pressure Iran.

The president has previously backed away from threats of severe escalation in the war, which has inflicted significant damage to the world economy since the United States and Israel launched attacks in late February. The Trump administration also has few obvious options for ramping up economic pressure, as the United States has imposed extensive sanctions targeting Iran’s economy and its leadership.

Without identifying particular countries, Mr. Trump seemed to suggest that he could target nations that buy Iranian oil. He referred to tactics that Iran has used to circumvent the U.S. sanctions that it weathered for years before the war began. The Treasury Department could impose secondary sanctions on buyers of Iranian oil, such as China, but that would ratchet up tensions ahead of President Xi Jinping’s visit to the United States, scheduled for September.

Many neighboring countries in the Gulf region also have significant economic ties to Iran. The United Arab Emirates announced a total embargo on trade and transactions with Iran on Monday. The announcement came hours after a call from Mr. Trump to the Emirati leader, Sheikh Mohammed bin Zayed.

“ANY country that allows its financial institutions, businesses, airports, or government entities to provide any type of lifeline to Iran will itself face TREMENDOUS Economic Consequences,” Mr. Trump wrote on Wednesday. “Oil smuggling, swap lines, cash transfers, exchange houses, ship registries, front companies — It all needs to stop NOW. You know who you are.”

Mr. Trump asserted, as he has since the opening days of the war, that victory was just over the horizon, and that Iran was “on the ropes” and “hanging by a thread.” But analysts have said that Iran shows no signs of capitulating and may step up attacks on U.S. allies.

International sanctions on Iran helped lead to the 2015 nuclear deal, an agreement negotiated by President Barack Obama that tightly restricted Iran’s ambitions to develop a nuclear weapon in exchange for ending sanctions that had crippled its economy. Mr. Trump tore up that deal three years later and reimposed the sanctions, which pushed Iran into another severe economic crisis.

But in the wake of Mr. Trump reneging on the nuclear pact, Iran has adapted to the sanctions, developing sophisticated smuggling routes and new markets, particularly for oil. Iran’s economy is badly damaged, but its leaders have repeatedly asserted control in crackdowns on protests.

Esmail Baghaei, the spokesman for Iran’s foreign ministry, said on Monday that new measures would have “no effect on Iran’s position.”

Alan Rappeport and Steven Erlanger contributed reporting.