FNA- Tehran called on London to speed up payment of its decades-old �450mln debt to Iran which was due to be spent for purchasing military equipment from Britain.

"This issue is important and is on agenda of the two countries and Iran is pursuing it seriously and I hope that Britain will show good will and pay back this money to Iran in the least period of time so that this old story will come to an end as soon as possible," Foreign Ministry Spokesman Bahram Qassemi told reporters in his weekly press conference in Tehran on Monday.

He added that London's debt to Iran was one of the issues discussed by the two countries' officials during the recent visit by British Foreign Secretary Boris Johnson, saying that more steps have been taken to resolve the problem.

British media reports said in November that Britain is planning to give back to Iran the money it paid for military equipment in order to free an Iranian-British citizen, Nazanin Zaghari, convicted in the country for espionage charges.

The reports added that Johson's visit to Iran in early December was aimed at consultations to free Zaghari by paying �400mln to Tehran; a claim which was rejected last month.

Iranian Ambassador to London Hamid Baeedinejad said in November that Britain is due to pay its �400mln debt to Tehran soon, dismissing any link between the payment and the case of Nazanin Zaqhari.

Over �400-mln ($596mln) sum will be transferred to the Central Bank of Iran �in the coming days�, Baeedinejad wrote on his Telegram channel.

The Iranian diplomat further expressed regret over certain media attempts to link the debt pay-off to the case of Zaghari.

The payment �with regard to a 1974 arms deal has nothing to do with the case of Nazanin Zaghari who has been arrested in Iran over security charges or to any other issue,� Baeedinejad told reporters.

Also last month, Qassemi said that �the British government�s debt pay-off to Iran has no connection to the case of Mrs. Nazanin Zaghari and these two issues are two separate cases.�

British Prime Minister Theresa May's spokesman also stressed at the same time that there was no link between the �400mln debt owed to Iran and the fate of Zaghari.