The Trump administration is poised to extend sanctions relief to Iran, avoiding imminent action that could implode the landmark 2015 nuclear deal, even as Secretary of State Rex Tillerson on Thursday accused Tehran of not respecting the entire agreement.

The administration's next move in its monthslong review of its Iran policy was expected later Thursday, when President Donald Trump faced a deadline to decide on extending waivers that allow Iran to conduct much of its international commerce.

The waivers were first issued by the Obama administration and are America's part of the deal's central bargain. In exchange for Tehran rolling back its nuclear program, the U.S. and other world powers agreed to suspend wide-ranging oil, trade and financial penalties that had choked the Iranian economy.

President Donald Trump has repeatedly criticized the deal, but has yet to pull out of it. The White House is seeking ways to find that Tehran is not complying with the agreement.

"The Trump administration is continuing to review and develop its policy on Iran," Tillerson said at a news conference with British Foreign Secretary Boris Johnson in London.

Trump has made clear that "we must take into account the totality of Iranian threats, not just its nuclear capabilities," the top U.S. diplomat said, citing obligations to uphold regional and international security.

"Iran is clearly in defiance of these obligations," Tillerson said, pointing to its support of Syrian President Bashar Assad's government, cyber activity and testing of ballistic missiles.

Iran rejects that it has broken the agreement. And it can point to a U.N. report this week showing that Iran was meeting the conditions on its nuclear program set out in the accord. The July 2015 deal was reached by Iran, the U.S., Britain, France, China, Germany and Russia.

Trump faces a couple of deadlines.

Under U.S. law, the president must certify to Congress every 90 days whether Iran is adhering to the agreement. If the president doesn't certify compliance, Congress has 60 days to decide whether to re-impose sanctions lifted under the agreement.

The next certification deadline is Oct. 15.

But first Trump must decide to extend sanctions relief to Iran under a separate clock.

Administration officials say Trump was ready to do so and that no serious alternatives have been presented — with the caveat that Trump could still change his mind.

The bigger question they and people outside government are pointing to is the one in a month's time. Several officials and people close to the matter have described Trump as determined to "decertify" Iranian compliance with the nuclear deal at that point — a finding that would jeopardize the entire agreement.

The officials weren't authorized to discuss such internal deliberations and spoke on condition of anonymity.

Tillerson said talks continue with the president and his senior advisers, but "no decision has been made."

Trump, in an interview with the Wall Street Journal, said he is inclined not to certify Iranian compliance after having twice found it compliant at earlier deadlines.

Iran deal opponents inside and outside the administration argue that Tehran's full compliance is unproven, particularly on allowing nuclear inspections at military sites. They argue that at the very least Iran is violating the spirit of the agreement with its ballistic missile tests. Those, however, aren't specifically covered in the nuclear agreement.

Whatever step by the Trump administration on Thursday, it will set the stage for talks on the agreement's future with European allies and others during next week's U.N. General Assembly.

Standing beside Tillerson, Britain's Johnson compared the tensions over North Korea's nuclear advance with the relative certitude that the Iran deal has provided.

Johnson said there are two sides to the deal: The Islamic Republic behaving itself, and the U.S. and the others ensuring Iran enjoys economic benefits.

Iran, with its young population, "could be won over to a new way of thinking," Johnson said, adding that he has pushed that argument with Tillerson and other Americans.


Associated Press writer Bradley Klapper contributed to this report.