TEHRAN: Iranian Foreign Minister Mohammad Javad Zarif said on Tuesday the United Nations had abruptly withdrawn Tehran's last-minute invitation to highly anticipated peace talks on Syria “under pressure”.

“We regret that Secretary General Ban Ki-moon has withdrawn the invitation under pressure,” Zarif told reporters in Ashgabat before flying back to Tehran, the ISNA news agency reported.

Ban withdrew the invitation to Iran, the Damascus regime's main regional ally, less than 24 hours after it was issued despite reservations from the United States and Syrian opposition groups.

Iran refuses to consent to a transitional government in Syria, which was agreed in the first international gathering in June 2012 to end the deadly civil war.

“I made it clear in numerous phone conversations with the secretary general that Iran does not accept any preconditions to attend the talks,” Zarif said.

“It is also regretful that Mr Ban does not have the courage to provide the real reasons for the withdrawal,” he said, claiming that “Iran was not too keen on attending in the first place”.

Zarif added that had Tehran been represented, he would have sent his deputy because “the proper time to invite a foreign minister had already passed”.