Iran presented world powers on Wednesday with a proposal for new talks with the West, though Iranian President Mahmoud Ahmadinejad has ruled out negotiations over uranium enrichment, the U.N.'s central concern over his country's controversial nuclear program.

The United States said it hopes for a "serious, substantive" response from Iran and said it will study the proposal carefully, Reuters reported.

Foreign Minister Manouchehr Mottaki gave a package of proposals to diplomats representing the five permanent members of the U.N. Security Council and Germany in a meeting in Tehran attended by journalists.

The proposals come as the U.N. nuclear watchdog agency is holding a meeting in Vienna, Austria. The IAEA chief Mohamed ElBaradei has said his agency is locked in a "stalemate" with Iran and has urged Tehran to "substantively re-engage" with the Vienna-based watchdog to prove there are no military dimensions to its nuclear program.

President Barack Obama and European allies have given Iran until the end of September to take up an offer of nuclear talks with six world powers and trade incentives should it suspend uranium enrichment. If not, Iran could face harsher punitive sanctions.

But Iranian President Mahmoud Ahmadinejad said Monday that Iran considered the nuclear issue closed and rejected any halt to enrichment.

He said Iran was proposing to hold negotiations over a range of "global challenges" but the only nuclear issues that it was willing to discuss were mechanism to ensure the global use of peaceful nuclear energy, to promote disarmament and to halt nuclear proliferation.

Iran state radio, reporting on the package Wednesday, said "Iran is ready to ... help ease joint international concerns over the nuclear issue," but did not elaborate.

It said Iran aims to reach a "comprehensive agreement based on collective goodwill to achieve long-term cooperation and strengthen regional and global peace and security based on justice." It said the package looks at issues "beyond the nuclear file," including crises in Iraq, Afghanistan, Lebanon and the Palestinian territories.

The U.S. and some its allies believe Iran is secretly trying to build a nuclear weapon, an accusation denied by Iran, which says it aims only to generate electricity. The United Nations has demanded Iran halt enrichment, a process that can produce fuel for a reactor or the material for a warhead. Iran says it has a right to pursue enrichment for fuel.

The U.S., Britain, France and Germany urged Iran on Wednesday to hold talks to reach a comprehensive diplomatic solution to the international standoff over its nuclear program.