Iran will receive the first tranche of its funds which have been frozen due to US-led sanctions by the beginning of February. The State Department said that $550 million will be released as part of the deal over Iran's nuclear programme agreed with world powers last year.
The financial aspect of the sanctions led to a total of $4.2 billion of Iran's money being frozen in overseas bank accounts. It is due to be released in stages.
Iran came to a six-month agreement with the US, UK, China and Russia in November over its nuclear development programme. It is intended to be a temporary step prior to a permanent deal on the issue.