Iran wants guarantees that it won't face U.N. sanctions before it is prepared to restart negotiations over its nuclear program, Germany's foreign minister said Friday.

Foreign Minister Frank-Walter Steinmeier called the condition unacceptable.

"I have always said that we must begin negotiations without preconditions. ... That is why Iran must understand we cannot come to the negotiating table when every day new centrifuges are being constructed," Steinmeier told reporters.

The foreign minister said Iran, in its response to an international package of incentives, was willing to hold new talks provided the five permanent members of the U.N. Security Council and Germany pledge to hold off on U.N. sanctions.

The six nations drew up the incentives package in hopes of persuading Iran to return to negotiations and suspend uranium enrichment. The U.N. Security Council gave Iran until Aug. 31 to suspend uranium enrichment work or face the threat of economic and diplomatic sanctions.

Steinmeier welcomed U.N. Secretary-General Kofi Annan's plans to visit Iran in the coming days and said he hoped Annan would make it clear that the international community expected Iran to come back to negotiations without conditions.

"I hope that the U.N. secretary-general can make that once again clear in Tehran," Steinmeier said on arrival at an EU foreign ministers meeting in Brussels that focused on European efforts to assemble an expanded U.N. peacekeeping force for southern Lebanon.

Earlier Friday, French President Jacques Chirac called Iran's response to the incentives package a "little ambiguous." Tehran's response, made on Tuesday, has been widely judged insufficient, but Germany, among others, has said the door to negotiations remained open.

Iran insists its nuclear program is for peaceful purposes and is aimed at generating power. But the United States and many of its European allies suspect it wants enriched uranium because it can also be used to make nuclear weapons.