Berlin  - German Foreign Minister Frank-Walter Steinmeier found Iran uncooperative during nuclear talks Monday in Berlin and called on Tehran to stop playing for time with the West and act to restore lost trust, German delegation sources said

Aides described Steinmeier as disappointed after the talks about Iran's nuclear programme.

Iranian Foreign Minister Manouchehr Mottaki had requested the meeting, according to the German account.

Steinmeier demanded the Iranians halt uranium enrichment and provide missing information about their research to the International Atomic Energy Agency (IAEA), the UN nuclear watchdog agency.

The atmosphere had already seemed cool as the two ministers briefly posed for pictures before the hour and a half of talks.

"Our offer is on the table. We hope Iran will give a constructive answer," Steinmeier spokesman Jens Ploetner said earlier, referring to proposals in June by world powers.

About 50 members of the banned Iranian opposition group National Resistance Council demonstrated outside the German Foreign Ministry in Berlin against the Mottaki visit.

Mottaki charged that their organization had conducted terrorist attacks and said its members should be arrested and put on trial by the International Criminal Court.

"Our offer is serious," Ploetner said, adding that if there was no positive response from Tehran, the alternative was further action through the UN Security Council.

Germany has joined the five permanent members of the security council in talks with Tehran.

The world powers have offered Tehran comprehensive economic and political cooperation, including providing nuclear fuel for its planned power stations, in return for a halt to what they see as Iranian moves toward making nuclear weapons. (dpa)