US President Donald Trump is expected this week to extend relief from economic sanctions to Iran as part of the nuclear deal, citing progress in amending US legislation that governs Washington's participation in the landmark accord, according to US officials and others familiar with the administration's deliberations.

But Trump is likely to pair his decision to renew the concessions to Tehran with new, targeted sanctions on Iranian businesses and people, the six people briefed on the matter said. The restrictions could hit some firms and individuals whose sanctions were scrapped under the 2015 nuclear agreement, a decision that could test Tehran's willingness to abide by its side of the bargain.

The individuals two administration officials, two congressional aides and two outside experts who consult with the government weren't authorized to speak publicly on the matter and demanded anonymity. They cautioned that Trump could still reject the recommendation from Secretary of State Rex Tillerson, Defense Secretary James Mattis and national security adviser H.R McMaster and that no final decision had been made. They said heated discussions were going on within the administration and with key Republican lawmakers.

The State Department and White House didn't immediately respond to requests for comment.

Trump must decide by Friday to extend the nuclear-related sanctions relief for Iran's central bank or re-impose the restrictions that President Barack Obama suspended two years ago.

The old, central bank sanctions largely cut Iran out of the international financial system, and are considered to be the most powerful of the penalties imposed by the U.S. during the Obama era, along with global penalties for buying Iranian oil. Some Iran hawks want to see both sets of restrictions return, but the six people with knowledge of Trump's plans say the president isn't planning to reinstate either at this point.

The individuals said Trump's top national security aides appear to have successfully made a different case to the president: Waiving anew for 120 days the nuclear-linked sanctions while simultaneously imposing new measures to punish Iran's ballistic missile testing, alleged terrorism support and human rights violations.

Such a balance could satisfy Trump's demand to raise pressure on Iran, while not embarking on a frontal assault on the most central trade-offs of the nuclear agreement. While the US and other world powers rolled back economic restrictions on Tehran, the Iranians severely curtailed their enrichment of uranium and other nuclear activity.

Trump has complained that many of the Iranian restrictions expire next decade and has vacillated between talk of toughening the deal and pulling the US out entirely.