"I think Iran will come along. They've been battered and bruised and, you know, they're out there. They need some help. There are big sanctions, as you know, tremendous sanctions," Trump told reporters alongside Egypt's President Abdul Fattah al-Sisi.
"I'd love to take the sanctions off when they're ready to talk. But they can't really survive with those sanctions," he added ahead of a summit in Sharm al-Sheikh.
Trump on Monday clinched the release of 20 Israeli hostages in exchange for hundreds of Palestinian political prisoners in a complex international deal he says will bring the devastating two-year-old war in Gaza to a close.
A troika of European powers triggered the reimposition of international sanctions on Iran last month, accusing Tehran of spurning diplomacy and nuclear inspections.
Trump reinstated the so-called "maximum pressure" campaign of US sanctions when he resumed office in January.
Iran denies seeking a nuclear weapon, has rejected a US demand that it renounce domestic enrichment and sees sanctions as a violation of international law.