Secretary of State Rex Tillerson said on Friday that the State Department is working to deliver on President Donald Trump’s promise to “fix” the Iran nuclear deal.

“The president said he is either going to fix it or cancel it. We are in the process of trying to deliver on the promise he made to fix it,” Tillerson told the Associated Press.

The next periodic recertification of the nuclear deal is due on January 12. When the previous 90-day review came due in October, President Trump refused to certify Iranian compliance but did not kill the nuclear deal, effectively passing the ball to Congress.

Critics of the nuclear deal were simultaneously surprised by Trump’s tough stance and displeased that he did not completely terminate the deal worked out by President Barack Obama. During the campaign, Trump called the Iran deal an “embarrassment” and “one of the worst and most one-sided transactions the United States has ever entered into.”

The White House said in October that it would work with Congress to strengthen the nuclear deal. On Friday, Tillerson indicated the administration is talking with congressional leaders “on a very active basis” about ways to improve the arrangement.

“I don’t want to suggest we’re across the finish line on anything yet,” Tillerson cautioned. “I think that’s why the president has not made a final decision either. If it’s not the twelfth but if we’re just talking about it’s imminent within some short period of time, we’ll see. But it will be the president’s decision to make.”

A congressional aide told the Associated Press that Sens. Bob Corker (R-TN) and Ben Cardin (D-MD) of the Foreign Relations Committee visited the White House on Thursday to discuss the Iran nuclear deal with National Security Adviser H.R. McMaster. Corker is not President Trump’s favorite member of the Republican caucus, to put it mildly, in part because Trump has publicly blamed him for making compromises that allowed President Obama to put the nuclear deal in place.

The AP mentioned changes that would primarily address President Trump’s annoyance with having to certify Iranian compliance every 90 days, either by removing the requirement or requiring it much less frequently. Tillerson spoke of longer-term changes that would shore up nuclear restrictions on Iran that are due to expire soon and possibly impose new restrictions on Iran’s long-range missile program.

Tillerson also criticized the European Union for failing to support protesters in Iran as strongly as the United States has. European leaders are generally in favor of keeping the nuclear deal in place.

“We’re a bit disappointed that the European Union has not taken a more definitive stance in supporting those voices within the country that are calling for reform,” he said.

On Thursday, the U.S. Treasury Department sanctioned five Iran-based business entities for aiding Iran’s effort to develop intercontinental ballistic missiles. Treasury Secretary Steven Mnuchin’s statement alluded to the protests currently underway against the regime in Tehran:

These sanctions target key entities involved in Iran’s ballistic missile program, which the Iranian regime prioritizes over the economic well-being of the Iranian people.  As the Iranian people suffer, their government and the IRGC fund foreign militants, terrorist groups, and human rights abuses.

The United States will continue to decisively counter the Iranian regime’s malign activity, including additional sanctions targeting human rights abuses.  We will not hesitate to call out the regime’s economic mismanagement, and diversion of significant resources to fund threatening missile systems at the expense of its citizenry.

The Iranians ostentatiously issued a warning on Monday that “the international community must be prepared for the U.S. possibly pulling out of the JCPOA.” JCPOA is the acronym for the formal name of the nuclear deal, the Joint Comprehensive Plan of Action.

“It’s been more than a year that the US president has sought to destroy the JCPOA with all his efforts,” Deputy Foreign Minister Abbas Araghchi said. “We in Iran are prepared for any scenario. The international community and our region will be the biggest loser, since a successful experience in the international arena will be lost. Our region will not become a safer region without the JCPOA.”