The five permanent members of the UN Security Council and Germany on Tuesday offered direct dialogue with Iran to solve the ongoing nuclear standoff with the Islamic Republic. 

A joint statement from the six nations -- Britain, China, France, Russia and the US plus Germany -- called on Iran to "take this opportunity for engagement with us and thereby maximize opportunities for a negotiated way forward.

"We remain firmly committed to a comprehensive diplomatic solution, including through direct dialogue," the so-called P5+1 nations said in a statement read to a closed-door meeting of the International Atomic Energy Agency (IAEA) board of governors in Vienna.

The six voiced serious concern at Iran's atomic advances and increasing restrictions on UN inspectors trying to keep track of them, but did not mention toughening sanctions as a way to rein in Iran.

Sanctions threats have been common in statements by Western members at earlier IAEA meetings. But Russia and China oppose further punitive steps.