VIENNA - Talks between Iran and major powers on Iran's nuclear issue will continue past Tuesday for a "couple of days", while the negotiations entered the most difficult and sensitive part of the talks, European Union foreign policy chief Federica Mogherini told reporters on Tuesday in Vienna.

The remarks of Mogherini came when several foreign ministers from six world major countries are finishing their meetings with their Iranian counterpart in the ongoing Iranian nuclear talks in the capital city of Vienna.

"We are continuing the negotiation ... Some ministers are leaving, but will be back in the coming hours or days," she said, rejecting the idea that the talks could be once again extended as the ministers are leaving Vienna.

There are still gaps between Iran and western states as the talks are approaching the self-imposed deadline of July 7.

The EU foreign policy chief said the deadline of the talks could be treated in a flexible way to give the negotiators more time to finalize the deal.(Xinhua)