President Donald Trump said late Tuesday he's pulling back on his threats to launch devastating strikes on Iran, swerving to deescalate the war less than two hours before the deadline he set for Tehran to capitulate or else a "whole civilization will die tonight."

Trump said he was holding off on his threatened attacks on Iranian bridges, power plants and other civilian targets, subject to Tehran agreeing to a two-week ceasefire and reopening of the Strait of Hormuz, the pivotal waterway through which a fifth of the world's oil is transported during peacetime. He also said Iran has proposed a "workable" 10-point peace plan that could help end war the U.S. and Israel launched on Feb. 28.

Iran's Supreme National Security Council said it has accepted a two-week ceasefire in the war and that it would negotiate with the United States in Islamabad beginning Friday. "It is emphasized that this does not signify the termination of the war," the council's statement said.

In a post on his social media site, Trump said that provided Iran agreed "to the COMPLETE, IMMEDIATE, and SAFE OPENING of the Strait of Hormuz" he would "suspend the bombing and attack of Iran for a period of two weeks."

Since the war began on Feb. 28, Trump has repeatedly backed off of deadlines just before they expire.

Trump says talks with Pakistani officials helped lead to his decision to delay bombing campaign

In his social media post, Trump said he decided to delay an expansion of U.S. strikes "based on conversations" with Pakistan Prime Minister Shehbaz Sharif and Gen. Asim Munir, Pakistan's powerful army chief.

READ MORE: Pakistan urges Trump to extend Iran deadline

Sharif, in a post on the social platform X earlier Tuesday, urged Trump to extend his deadline by two weeks to allow diplomacy to advance. Pakistan has been leading negotiations.

Sharif used the same post to ask Iran to open the Strait of Hormuz for two weeks.