Iranian President Mahmoud Ahmadinejad has called off plans to speak to the UN Security Council because a visa to allow him into the U.S. did not arrive in time, an official said Friday.

Ahmadinejad was expected to address the council at UN headquarters in New York on Saturday. The council is expected to vote soon on whether to impose further sanctions on Iran for its refusal to stop enriching uranium.

Mohammad Mir Ali Mohammadi, press secretary of Iran's mission at the UN, said Friday that the U.S. failed to deliver a visa to the U.S. Embassy in Bern, Switzerland, in time for Ahmadinejad to fly to New York on Saturday.

Ahmadinejad had wanted to address the council before it votes on sanctions.

According to Mohammadi, Russia and China want the vote to be postponed, and if it is held at a later date, Ahmadinejad would then decide whether he would go.

The council has finished work on a draft resolution that would impose additional sanctions on Iran.

The sanctions would increase pressure on Iran to stop uranium enrichment, a process by which a country can produce fuel for nuclear reactors or fissile material for nuclear bombs.

Iran says its uranium enrichment produces fuel for nuclear power plants and is used to generate electricity, but the U.S. and its allies say they fear Iran could be building nuclear weapons.

With files from the Associated Press