WASHINGTON (AP) — The Trump administration is poised to extend sanctions relief to Iran, avoiding imminent action that could implode the landmark 2015 nuclear deal.

But the move expected Thursday comes as the White House seeks ways to find that Tehran is not complying with the agreement. President Donald Trump has repeatedly criticized the deal, but has yet to pull out of it.

Trump is working against a Thursday deadline to decide whether to extend the sanctions waivers, which were first issued by the Obama administration.

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 sanctions that had choked the Iranian economy.

Administration officials say Trump is ready to extend the waivers and that no serious alternatives have been presented. But they cautioned that Trump could still change his mind, and they said he remains determined to "decertify" Iranian compliance with the nuclear deal by a separate, mid-October deadline — a finding that would jeopardize further sanctions relief.

The officials were not authorized to discuss internal deliberations and spoke on condition of anonymity.

Both the sanctions relief and the certification deadlines come amid a broader administration review of Iran policy that is likely to lead to the adoption of a harder line, including the imposition of significant new non-nuclear sanctions, when it is completed next month.

The extension of sanctions relief is expected to be accompanied by a strong statement outlining the administration's oft-stated complaints that Iran is a destabilizing force in the region.

The statement will set the stage for discussions on the future of the agreement with European allies and others during next week's United Nations General Assembly as well as the internal administration debate over whether Trump should report to Congress that Iran is in compliance with the deal.

The U.N. atomic watchdog said earlier this week that Iran continues to meet its obligations under the accord negotiated among Iran, the U.S., the other four permanent members of the U.N. Security Council and Germany. But Iran deal opponents inside and outside the administration argue that Tehran's full compliance, particularly on allowing inspections at military sites, has not been tested and is not yet proven. They also argue that at the very least Iran is violating the spirit of the agreement with destabilizing behavior such as ballistic missile tests that is not specifically covered by the terms of the nuclear deal.

Trump himself, 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.

Supporters of the deal, including some nuclear experts and former Obama administration officials involved in negotiating the agreement, have made the case that decertification would be counter to U.S. national security interests because it would provide Iran with a pretext to claim Washington is in breach of the deal and undermine American credibility in future international negotiations.

Under U.S. law, the president must certify to Congress every 90 days whether Iran is meeting its commitments to the agreement. If the president does not certify compliance, Congress would have 60 days to decide whether to re-impose sanctions that were lifted under the agreement.

The next certification deadline is Oct. 15.

Officials familiar with the administration debate say Trump is weighing several options, only one of which would certify that Iran is abiding by the deal. The others call for decertification but differ on the next steps, ranging from walking away from the agreement and immediately re-imposing sanctions to remaining a party to the deal while trying to strengthen it through congressional action and supplemental accords.

The certification option, presented earlier this week by Secretary of State Rex Tillerson, would find Iran to be in compliance in line with the IAEA conclusion. Yet it would also make clear that the deal is flawed and must be fixed if it is to be preserved, according to the officials.

It would maintain sanctions relief but say that if the flaws in the deal are not addressed by January, Iran should be decertified on the grounds that the accord is no longer in U.S. national security interests. The fixes, involving the extension of now time-limited restrictions on Iran's ability to enrich uranium, would be negotiated with the other parties to the agreement.

The most well-known of the decertification options was presented publicly last week by U.S. Ambassador to the United Nations Nikki Haley, which would declare Iran to be in violation of the deal, maintain sanctions relief, and leave it to Congress to determine the next steps. Haley also suggested that because Iran has continued its ballistic missile program in defiance of the U.N. Security Council resolution that enshrined the nuclear deal, it could be held in breach.

A third option would decertify Iran on national security grounds under U.S. legislation but not immediately walk away from the deal. It would instead have Trump issue a new executive order setting out a timeline for the agreement to be amended or supplemented with bans or further limitations on uranium enrichment and ballistic missile testing, according to the officials.

Another option being floated is to decertify Iran and threaten to restore nuclear sanctions on Iran at any point as well as so-called "secondary sanctions" that could cut off European and other banks and businesses that do business with Iran from the U.S. financial system.