Iran s Foreign Minister Hossein Amir-Abdollahian in Tehran. AFP
Hossein Amir-Abdollahian had been due in New York to attend a UN Security Council meeting on the Israeli war on Gaza.
"The Americans issued visas for me and all my companions at 1:00 am (2130 GMT)," Amir-Abdollahian said after a cabinet meeting.
The delay meant it was "not possible" for the Iranian delegation to attend the meeting, which is due to begin at 1430 GMT, he added.
Amir-Abdollahian said that despite his absence, Iran would exert "all efforts" for an extension to a humanitarian truce deal in Gaza.
Palestinian resistant group Hamas is due to release a sixth batch of Israeli captives in exchange for Palestinian prisoners later Wednesday before the six-day truce expires early on Thursday.
Iran-backed Hamas is willing to extend the truce for four more days, a source close to the group said on Wednesday.
In principle, the United States is required to allow access to the United Nations for foreign diplomats.
But in 2020, Tehran accused Washington of refusing a visa to then-foreign minister Javad Zarif for a visit to UN headquarters.
The two governments have had no formal diplomatic ties since 1980.
* This story was edited by Ahram Online.