Oren Dorell

USA TODAY

WASHINGTON —Secretary of State Rex Tillerson said Wednesday Iran's behavior is still concerning despite its compliance with the nuclear deal negotiated with the U.S. and five other world powers to limit Tehran's nuclear program in return for lifting economic sanctions.

Tillerson listed several U.S. grievances over Iran's actions in the Middle East, saying they would be addressed in a comprehensive Iran policy under development by the Trump administration.

“Iran is the world’s leading state sponsor of terrorism and Iran is at this time involved in multiple conflicts that undermine U.S. interest,” Tillerson said in the State Department’s Treaty Room.

In Syria, Iran supports President Bashar Assad's regime “even as it conducts atrocities against its own people, including the use of chemical weapons,” he said. Iran has also continued to support some Iraqi militant groups that have "been undermining security in Iraq for years, Tillerson added.

Tillerson noted that Iran provides weapons training and funding to Hamas and other Palestinian terrorist organizations as well as the Houthi militias group in Yemen.

“The nuclear deal failed to achieve the objective of a non-nuclear Iran,” Tillerson said. “The Trump administration has no intention of passing the buck to future administrations on Iran."

“Iran is compliant through April 18th with its commitments under the Joint Comprehensive Plan of Action,” Secretary of State Rex Tillerson wrote Tuesday in a letter to House Speaker Paul Ryan.

Tillerson said President Trump has ordered his national security staff to conduct an interagency review of “whether suspension of sanctions related to Iran pursuant to (the nuclear deal) is vital to the national security interests of the United States.”

Such certification from the secretary of State is required every three months by the Iran Nuclear Agreement Review Act passed by Congress in 2015.

Trump frequently criticized the nuclear agreement negotiated by the Obama administration after it was reached in 2015 and during his presidential run in 2016.

He called the negotiations “amateur hour,” in an op-ed in USA TODAY. He told Newsmax the deal was “horrible” and “dangerous.” In October, Trump said Iran "should write us a letter of thank you" for "the stupidest deal of all time."

On the campaign trail, Mike Pence said the deal should be “ripped up” after consultation with allies. As a candidate, Trump said only that the deal should be renegotiated.

Tillerson’s letter makes clear Trump is now looking for more ways to pressure Iran.

At his confirmation hearing, Tillerson criticized the nuclear deal, saying it would fail to prevent Iran from someday purchasing a nuclear weapon, and that while it does freeze the Iranian nuclear program’s progress, “it does not ultimately deny their ability to have a nuclear weapon,” in the future. He told senators he would “review” the agreement.

“When the interagency review is completed, the administration looks forward to working with Congress on this issue,” Tillerson wrote Tuesday.

Kelsey Davenport, director for non-proliferation policy at the Arms Control Association, praised Tillerson’s certification on Twitter, saying it’s a good sign for a sanctions waiver renewal due next month.

Tillerson’s statement is a sign the U.S. will find ways to put pressure on Iran outside of the nuclear agreement, said Mark Dubowitz, executive director of the Foundation for the Defense of Democracies and a critic of the nuclear deal who has testified on Capitol Hill on sanctions.

It “underscores the Trump administration’s commitment to ramp up pressure on Iran through the use of sanctions tied to terrorism and other malign activities,” Dubowitz said.