Iran's negotiators who are tasked with disposing the country's stockpile of enriched uranium were focusing on a US-supported plan to have the material exported to another country moments before the June 30 deadline for a final nuclear deal with six world powers.

Iran reportedly has over eight tons of enriched uranium that may be turned into the fissile core of at least a dozen atomic bombs if further enriched to weapons grade.

Ahead of the Tuesday target date for an agreement, brokers were already running out of time to set a decision, but diplomats emphasised that the concerned parties had yet to agree on that solution.

Although Iran has maintained that it does not desire nuclear arms and that it is only enriching to make reactor fuel and for other non-military usage, its senior officials have publicly stated that they do not want to ship out the low-enriched uranium supply in initial negotiations.

The country is still ironing out an all-inclusive deal with the US, Britain, France, Germany, Russia, and China that would hinder Iran from making nuclear weapons in exchange for relief of sanctions.

Another option is to change the enriched uranium into a form that cannot be employed for weapons or shipping the material abroad for storage, possibly in Russia. Moscow would then convert the uranium and Iran will be given a large share of profits from any sale.

The US bans almost all trade with Iran except in the export of medical and agricultural equipment, humanitarian aid, and "informational" materials like films, the BBC wrote in March.

The EU restricted equipment that can be used to enrich plutonium, implemented an asset freeze on people that the EU believed were helping advance the nuclear program, banned financial transactions with Iranian banks, and forbade the import, purchase and transport of Iranian crude oil and natural gas.

Japan and South Korea imposed sanctions similar to those of the EU.

Sanctions by the UN, meanwhile, banned the supply of heavy weaponry and nuclear-related technology, barred arms exports, and implemented asset freeze on major companies and individuals.