Congress rejected Iran’s choice for ambassador to the United Nations, outraged by the prospect of a member of a group responsible for the 1979 takeover of the U.S. Embassy in Tehran stepping on U.S. soil. The move forces President Barack Obama to make a decision that could have serious diplomatic repercussions.

In a rare unanimous vote Thursday, the House backed a bill that would bar entry to the U.S. to an individual found to be engaged in espionage, terrorism or a threat to national security. The vote came four days after similar action in the Senate and sends the bill to the White House.

The Obama administration opposes the selection of Hamid Aboutalebi because of his alleged participation in a Muslim student group that held 52 Americans hostage for 444 days during the takeover. American officials have told Iran that Aboutalebi is unacceptable, and the State Department indicated Thursday that the issue could be resolved if Tehran simply withdrew the nomination.

Iran has called U.S. rejection of Aboutalebi “not acceptable,” with Iranian state television quoting Foreign Ministry spokeswoman Marzieh Afkham saying Aboutalebi is one of the country’s best diplomats and argued that he previously received a U.S. visa. Aboutalebi has insisted his involvement in the group Muslim Students Following the Imam’s Line was limited to translation and negotiation.

Against the backdrop of ongoing nuclear talks between Iran and the West, the latest flare-up has drawn attention in Iran, where the front-page headline of the Etemad newspaper blared, “Dispute over Iran’s Ambassador,” and “Our ambassador has been chosen and won’t be changed.”

In practical terms, Obama must decide whether to sign or veto legislation that could upset host country agreements with numerous nations. Hours after the House vote, White House officials declined to say what the president would do. Spokesman Jay Carney said the administration was continuing to tell Iran that its choice was unacceptable.

Proponents of the legislation said Obama’s choice is clear.

“When Iran said they wanted to send someone to New York City, to the United Nations under diplomatic immunity, who is affiliated with those who captured our embassy and held them for 444 days, something’s wrong there and everyone realizes that,” Rep. Doug Lamborn, R-Colo., who sponsored the bill in the House, said in an interview.

Sen. Ted Cruz, R-Texas, took the lead on the measure in the Senate, sponsoring it and securing the support of Democrats and Republicans. He pressed Obama to sign the bill into law.

“We, as a country, can send an unequivocal message to rogue nations like Iran that the United States will not tolerate this kind of provocative and hostile behavior,” Cruz said in a statement.

The overwhelming reaction and swift action on the bill reflect congressional suspicion about the administration’s outreach to Iran and the nuclear talks. Republicans and Democrats have repeatedly warned the administration about possible concessions to Iran.

Denying visas to U.N. ambassadorial nominees or to foreign heads of state who want to attend United Nations events in the United States is rare, if not unprecedented.

In past, problematic cases — such as with a previous Iranian nominee in the early 1990s and more recently with Sudanese President Omar el-Bashir — the U.S. has either signaled opposition to the applicant and the request has been withdrawn, or the State Department has simply declined to process the application. Those options, as well as approving or denying the application, are available in the current case.