Five Americans held hostage in Iran have been released as part of a controversial deal between Tehran and Washington.

The United States paid $US6 billion to free five citizens from Iran who had been held in the notorious Evin prison.

Iran’s charges against the hostages have been described by the US as baseless and used to create political leverage.

The four men and one woman touched down in Doha, Qatar, on Monday where they were greeted by US officials, and then boarded a flight back to Washington.

The US however has been criticised over the deal, with suggestions the funds sent to Tehran would be used to develop nuclear weapons and support terrorism.