The European Union, about to ratchet up sanctions against Iran over its disputed nuclear drive, will keep up the pressure on Tehran failing a breakthrough in talks, British Foreign Secretary William said Monday.

"Today we expect to agree fresh sanctions on Iran as a result of its nuclear programme and its continued failure to satisfy the world that that programme is for peaceful purposes," Hague said on stepping into a meeting of the bloc's 27 foreign ministers.

"This is a sign of our resolve in the European Union," he added, "that we will step up the pressure, we will intensify the pressure and we will continue to do so over the coming months unless negotiations succeed."

The new package of sanctions is expected to target EU dealings with Iran's banks, as well as trade and gas imports, diplomatic sources said.

EU foreign policy chief Catherine Ashton said it was "very very important that Iran is sent a very strong signal from this European Union foreign affairs council that we want to see a negotiated agreement."

Previous sanctions, in particular a biting oil embargo that came into effect in July, are "quite clearly having an effect," she told reporters.

Ashton, who represents global powers in talks with Iran on its nuclear programme, said the sanctions aimed "to persuade Iran to come to the table."

According to a diplomat who asked not to be named, ministers will agree for the first time Monday to hit Iran's telecoms sector, targetting companies believed to provide financial support for Tehran.

All dealings between European and Iranian banks will meanwhile be banned above a certain "relatively low" threshold, although exceptions will be allowed in some medical and humanitarian cases, the diplomat said.

Short-term export credit guarantees will be also barred, joining the medium- and long-term guarantees already banned.

Imports of Iranian gas will be prohibited, a symbolic gesture since the amounts involved are small, but the move sits alongside July's much more significant ban on imports of Iranian oil.

Sales of graphite or aluminium which could be used in Iran's nuclear or ballistic missile programmes are also to be closed down, with other measures targetting its shipping industry.

An extra 30 companies will be put on a list of firms hit by an EU assets freeze.