Iran condemned on Thursday restrictions imposed by the US government on diplomats at its mission in New York, where the United Nations is headquartered.
Tehran's foreign ministry said the US State Department was preventing three embassy employees from "continuing their activities", calling it a "violation" of Washington's obligations.
"The Ministry of Foreign Affairs of the Islamic Republic of Iran condemns the tightening of restrictions imposed on the Iranian diplomatic mission to the United Nations in New York," the ministry said in a statement.
It was not immediately clear when the restrictions targeting Iran were imposed by Washington.
Relations between Tehran and Washington were severed after the 1979 Islamic revolution and the subsequent hostage crisis at the US embassy.
At an annual meeting of the UN General Assembly in September, Washington prohibited Iranian diplomats stationed in or visiting New York from shopping at warehouse stores and purchasing luxury goods.
The diplomatic missions of Russia and Cuba are also subject to restrictions in the United States.
Iran and the United States began negotiations in April, mediated by Oman, over Tehran's controversial nuclear program.
But those talks stalled after Israel's surprise attack on Iran on 13 June, which triggered a 12-day conflict between the two countries that also saw the US strike three major Iranian nuclear sites.
Last month Iran's Supreme Leader Ayatollah Ali Khamenei said US President Donald Trump's government was "not worthy" of any contact or cooperation with the Islamic Republic.