“President Trump does not bluff and he is prepared to unleash hell. Iran should not miscalculate again,” Leavitt told reporters in a press briefing.

“If Iran fails to accept the reality ​of the current moment, if they fail to understand that they have ​been defeated militarily, and will continue to be, President Trump will ⁠ensure they are hit harder than they have ever been hit before,” she ​said.

As the joint US-Israeli war on Iran entered its fourth week, there have ​been efforts by multiple countries, such as Pakistan, Turkey and Egypt, to mediate.

Iran is still reviewing a US proposal to end the war, despite an initial response that was negative, ​a senior Iranian official told Reuters on Wednesday, indicating that Tehran had so ​far stopped short of rejecting it outright.

Talks with Iran were still underway, Leavitt said.

“Talks ‌continue. ⁠They are productive, as the president said on Monday, and they continue to be,” she added.

Citing unnamed sources, media outlets on Tuesday reported that Washington sent Tehran a 15-point plan on ending the war.

Leavitt said on Wednesday that elements of ​the reports were not ​fully accurate, but ⁠she did not provide specifics.

“The White House never confirmed that full plan. There are elements of truth to it, but some ​of the stories I read were not entirely factual, so ​I am ⁠not going to negotiate on behalf of the president here at the podium,” Leavitt said.

Global equity markets regained some ground while oil prices dipped on Wednesday after the ⁠reports ​about the plan, with investors hoping for an end ​to a war that has disrupted global energy supplies and raised inflation concerns.