Iran's top nuclear official has warned that Tehran needs "tangible progress" from a critical meeting with European governments later this month to avoid a breakdown of talks on the controversial nuclear programme.

In an interview with the Financial Times, Hassan Rowhani, head of the supreme national security council, said Iran would be willing to continue the negotiations for a few more months - but only if the UK, France and Germany signalled that Iranian ideas recently put forward could be the basis of the negotiations.