The president wrote on Truth Social that the effort was being paused to provide the best possible conditions for reaching a final peace agreement with Iran.
According to Trump, the decision was made after pressure from, among others, the mediating country Pakistan and because "great progress towards a full and final agreement" had been made.
The blockade of Iranian ports remains in place.
The operation, dubbed "Project Freedom," began on Monday. The aim has been to assist nearly 23,000 sailors from 87 different countries who have been stranded in the Gulf for more than two months, Sen. Marco Rubio said on Tuesday evening.
Shortly after Trump's announcement, reports came from state-run Iranian media that Iranian Foreign Minister Abbas Araghchi had landed in Beijing for talks with his Chinese counterpart Wang Yi.
The United States has previously urged China to put pressure on Iran regarding a peace agreement.
Marco Rubio also met with Wang Yi last week, and Donald Trump is traveling to Beijing in a week to meet President Xi Jinping.
