The foreign ministers of the European Union’s three biggest powers, France, Britain and Germany sent a strongly worded letter to Hassan Rohani, Iran’s chief nuclear negotiator, warning that resuming nuclear activities ‘would bring the negotiating process to an end,’

‘The consequences could only be negative for Iran,’ the letter said.

On Thursday night the head of Iran’s nuclear agency said it may postpone resumption of uranium reprocessing.

‘No certain day is fixed for resumption of reprocessing. It is possible to postpone it some days,’ Gholamreza Aghazadeh, the head of Iran’s Atomic Organization, told the Tehran state-run television.

Yet, earlier in the day Rohani, Iran’s chief nuclear negotiator, said Tehran would resume some nuclear activities.

‘Continuation of negotiations in their present format is not possible for us,’ Rohani said, describing current talks as not balanced and costly for Iran.

British Prime Minister Tony Blair explicitly warned Iran on Thursday that the EU would support referral to the United Nations Security Council if Iran breaches its obligations.

The EU letter to Iran proposed ‘ministerial level talks’ to break the impasse and avoid a crisis.

Iran earlier told the EU it was fed up with the slow pace of talks, warning that time was running out, and that it will soon resume parts of its uranium enrichment program.

in November Tehran agreed to suspend all activities linked to the enrichment of uranium.

But Rohani recently said Tehran would no longer feel bound by the nuclear Non-Proliferation Treaty (NPT) if it was denied the right to pursue a full civilian nuclear energy program.