Iran said on Thursday it would attend a U.N. conference on the future of Afghanistan which was proposed by Tehran's old foe the United States and called for a regional solution to the crisis.

But Foreign Ministry spokesman Hassan Qashqavi said Iran had yet to decide who to send to next Tuesday's international meeting in The Hague, which will be attended by U.N. Secretary-General Ban Ki-moon, U.S. Secretary of State Hillary Clinton and delegates from more than 80 countries.

News of Iran's participation is likely to be welcomed by the new U.S. administration of President Barack Obama, who has offered a new beginning of diplomatic engagement with the Islamic Republic on a range of issues.

Clinton earlier this month said Iran would be invited to the meeting on Afghanistan, which battles a growing Islamist Taliban insurgency, in a U.S. overture which recognizes the Shi'ite Muslim power's influence in its troubled neighbor.

Iran and the United States have not had diplomatic ties for three decades and are now at odds over Tehran's nuclear work.

But analysts say they share an interest in ensuring a stable Afghanistan, where violence is at its highest level since the 2001 U.S.-led invasion.

Iran will participate, Qashqavi said. The level of participation is not clear.

Clinton is expected to provide details of a review of U.S. strategy toward Afghanistan and Pakistan, which is set to be released before the conference in the Dutch city.

AFGHANISTAN CRISIS

Iran says the United States is failing in Afghanistan but that Tehran is ready to help its eastern neighbor.

Foreign Minister Manouchehr Mottaki was quoted as saying a regional solution was needed.

Obama last month ordered the deployment of 17,000 extra U.S. troops to the country. Iran has often called for U.S. forces to leave the region, saying they are making the situation worse.

But both Tehran and Washington oppose the hardline Sunni Taliban and al Qaeda, back Afghan President Hamid Karzai and want stability, reconstruction and an end to drug trafficking.

We believe that a regional solution should be found for the Afghanistan crisis, the semi-official Fars News Agency quoted Mottaki as saying during a visit to Brazil.

Iran's goal in the region is to help peace, stability and calm which is necessary for the region's progress, he said.

Qashqavi said Iran would also attend a separate meeting on Afghanistan in Moscow this week.

In a major shift from the policies of his predecessor George W. Bush, who sought to isolate Tehran over nuclear work the West suspects is aimed at making bombs, Obama has offered to extend a hand of peace to Iran if it unclenches its fist.

Last week, in a televised address released to Middle East broadcasters, Obama made his warmest offer yet of a fresh start in relations with Iran.

Iran's Supreme Leader Ayatollah Ali Khamenei said on Saturday he had so far seen no change in U.S. behavior but Tehran would respond to any real policy shift by Washington. Iran says its nuclear program is for peaceful power purposes.

In other areas, the United States accuses Iran of sponsoring terrorism in the Middle East and of backing and arming Shi'ite militias in Iraq, charges Iran dismisses. But they also share an interest in Iraq's stability and territorial integrity.

(Editing by Samia Nakhoul)