It's time for the United States to hold Iran accountable.

The Trump administration is giving "strong indications" that it is preparing a case to decertify Iran's compliance with the international nuclear agreement, an expert says.

If that happens, though, some analysts believe it risks alienating U.S. allies. In addition to the United States and Iran, the 2015 nuclear agreement was signed by Britain, France, Germany, Russia, China and the United Nations.

The White House sent Nikki Haley, U.S. ambassador to the United Nations, to Vienna on Wednesday to meet with officials from the International Atomic Energy Agency, which is responsible for monitoring and verifying Iran's commitments under the 2015 agreement, known as the Joint Comprehensive Plan of Action.

On Thursday, Iran's state-run IRNA news agency quoted from a letter sent by Iran's foreign minister to the U.N. agency saying the country "is abiding by its duties and responsibilities" with regard to nuclear weapons and agreements. He accused Washington of using the issue "for ill-wishing political means."

During her visit, Haley "discussed the IAEA's verification and monitoring of Iran's nuclear-related commitments," according to a statement by the agency. It provided no additional information, and a statement from Haley's office discussed her visit but shed no light on imminent action.

Last week, Haley said the Tehran government should be held accountable for "its missile launchers, support for terrorism, disregard for human rights, and violations of U.N. Security Council resolutions. Iran cannot be allowed to use the nuclear deal to hold the world hostage."

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