British Foreign Secretary William Hague said Tuesday evening that Britain regrets that Iran was not prepared to negotiate seriously in the latest round of talks of the E3+3 in Moscow.

After the conclusion of the talks Hague said that the E3+3 approached the meeting ready to make progress.

In a statement, Hague said "Our position was consistent, clear and reasonable. There was a detailed and frank exchange on our respective proposals".

He noted that there remains significant differences on substance. The minister voiced regret that Iran was not prepared to negotiate seriously on specific concerns of the international community - in particular regarding 20 percent enrichment.

"This is a missed opportunity to address the serious concerns of the international community".

"We have been unable to set another round of talks at this stage".

However, Hague noted that nuclear experts from both sides will meet to offer further clarity on technical issues, following which the west would consider whether there is sufficient basis for further political talks.

"The E3+3 is united in reiterating that the onus is on Iran, which stands in contravention of six UN Security Council Resolution to take concrete steps to reassure the international community about its intentions.

The Foreign secretary stressed that Iran should not doubt the west's commitment to a peaceful, negotiated solution.

"But it should understand clearly that in order to achieve this it must be willing to take urgent, concrete steps to reassure the international community to which we will respond".

"Our door remains open for serious engagement and negotiations", he asserted. The minister pointed out that the EU oil sanctions will come into force on 1 July and until Iran chooses a different path the west will work with partners across the world to intensify the pressure further.