“We have already received the money from Britain and the funds are even being used,” Ali Salehabadi, governor of the Central Bank of Iran (CBI), told reporters. “Information on the [release of the] rest of [Iran’s] blocked sums will be progressively provided. Overall, the work is progressing well,” he said without further details on the sidelines of a cabinet meeting on Wednesday, according to the official IRNA news agency.

Salehabadi made the remarks hours after a report by Britain’s The Guardian newspaper quoted a senior Iranian government source as saying the £400million was still stuck in Oman. The official told the Guardian the problem was not with the UK government.

Speaking to the Entekhab news site on Sunday, Mahmoud Abbaszadeh-Meshkini, spokesperson for Iran’s parliament’s national security and foreign policy committee, also said Britain’s £400million debt had been “released at source”, adding that the transfer, presumably to an Omani bank, had not been a problem.

The important thing was to release the frozen money from the home country of Britain, he said, adding that he believed other steps – i.e. transferring the money to Iran from Oman – could not cause any problems.

Neither the CBI governor nor Abbaszadeh-Meshkini specified the nature of the difficulties expected in the repatriation of funds from Oman, which they described only as a “regional” or “neighbouring” country.

“The extent of the heist is unclear, and it’s unclear whether it was due to a banking problem in Oman or another issue, such as limits on the use of money by Brits,” wrote The Guardian.

Britain owed Iran £400 million ($530 million) for 1,750 Chieftain tanks and other vehicles purchased before the 1979 Islamic Revolution, almost none of which were delivered.

On March 16, British Prime Minister Boris Johnson announced that two British-Iranian dual nationals held by Iran had been released and would go home. Simultaneously, some media outlets affiliated with the Iranian state, including the Revolutionary Guards-linked Fars news agency (IRGC), reported that the two detainees had been released in exchange for the historic £400 million debt of Britain to Iran.

The British and Iranian governments have both claimed that there is no link between the debt and the case of those detained.

According to the Guardian, “one report” said only £1million of the money had been transferred to Tehran.

Muscat negotiated the release of the two British detainees, Nazanin Zaghari-Ratcliffe and Anoosheh Ashouri, who were freed after funds arrived in an Omani bank.

The Guardian also said there had been speculation that London might withhold the full release of the funds because it believes Iran failed to meet its end of the negotiated deal which should have allowed a third detainee Morad Tahbaz to be released from prison indefinitely. He was briefly released and then sent back to prison.

The UK Foreign Office stressed that the payment, made on the condition that it would only be used for humanitarian purposes, “was made in full compliance with UK and international sanctions and all legal obligations”. Iranian officials said Tehran had “full control” over how to spend the funds without mentioning conditions set by Britain.