Speaking in Copenhagen, Annan said the international community has an opportunity to "really move ahead" and resolve the issue of Iran's nuclear program.
Annan said the Iranians are now studying the incentives package, and he expressed hope they would respond soon.
In Tehran, Iran's Foreign Minister Manuchehr Mottaki said a "positive atmosphere" has been created that could help resolve the nuclear dispute.
Iran's Nuclear Program
THE COMPLETE PICTURE: RFE/RL's complete coverage of controversy surrounding Iran's nuclear program.
An annotated timeline
of Iran's nuclear program.