France said on Wednesday it wanted to bring together members of the U.N. Security Council after an International Atomic Energy Agency report said Iran had worked to develop an atomic bomb design.

Convening of the U.N. Security Council is called for, Foreign Minister Alain Juppe told RFI radio.

We cannot accept this situation which is a threat, said Juppe, adding that France was ready to toughen sanctions.

We need hard sanctions that prevent Iran from continuing to obtain resources that allow it to pursue its activities in violation of all international rules, said Juppe.

The report from the U.N. nuclear watchdog -- citing what it called credible information from member states and elsewhere -- listed a series of activities applicable to developing nuclear weapons, such as high explosives testing and development of an atomic bomb trigger.

Calling the report a real source of worry, Defence Minister Gerard Lonquet reiterated the need for tougher sanctions.

He told Canal+ television it was necessary to convince China and Russia, which are likely to oppose a fifth Security Council sanctions resolution against Iran.

(Reporting By Alexandria Sage and Sophie Louet; editing by Elizabeth Piper)