BERLIN, Jan 20 (AFP) - The U.S. Secretary of State Antony Blinken and European allies have maintained that it was still possible to revive the Iran nuclear deal but said "time is running out", after talks in Berlin Thursday.

Blinken while addressing reporters said, negotiators working in Vienna to salvage the 2015 accord with Tehran had seen "modest progress in the last couple weeks" but were taking nothing for granted.

"My own assessment, talking to all of our colleagues, is that returning to mutual compliance, it remains possible," Blinken said.

Speaking at a joint news conference, German Foreign Minister Annalena Baerbock said "urgent progress" was needed in talks aimed at rescuing the deal.

"The window for finding a solution is closing," she said.

"The negotiations are in a decisive phase. We need urgent, urgent progress, otherwise we will not be successful in reaching a joint accord."

Her French counterpart Jean-Yves Le Drian, also in Berlin for talks focused primarily on the Ukraine crisis, warned that "the negotiations cannot go on so slowly" with Tehran.

He complained that the progress in the meetings was "partial, timid and slow", adding it was crucial to now "pick up the pace" or risk failure.

Blinken agreed it was a "decisive moment" in the negotiations, adding "time is running out" to reach a deal.

Their comments came a day after U.S. President Joe Biden said it was "not time to give up" on the talks with Iran, insisting "there is some progress being made".

Negotiations to restore the landmark accord between Tehran and world powers, the United States, France, Britain, Russia, China and Germany began last year but stopped in June as Iran elected ultraconservative President Ebrahim Raisi.

The talks on the accord known as the JCPOA resumed in November.