United States/Iran: FACTBOX: U.S. disputes with Iran mask shared interests.

Section: General News - Iran has said it will attend a U.N. conference on Afghanistan on Tuesday, joining talks proposed by the United States, which wants a broader dialogue with Tehran.

But Iran has not decided who to send to the March 31 meeting in The Hague, a Foreign Ministry spokesman said on Thursday This month U.S. President Barack Obama offered a fresh start in ties with Iran after three decades of mutual hostility. His appeal marked a sharp shift of tone from former President George W. Bush's efforts to isolate the Islamic Republic.

Iran's Supreme Leader Ayatollah Ali Khamenei said later he had seen no change in U.S. behavior yet, but that his country would respond to any real policy shift by Washington.

Iran has said it is ready to help Afghanistan as it battles a growing Taliban insurgency. Its inclusion in the international conference at the behest of the United States is a recognition of the Shi'ite power's influence in its troubled neighbor.

Washington and Tehran are deeply divided on many issues, but also share important interests in Afghanistan and elsewhere.

AFGHANISTAN They are vying for influence in Afghanistan, but both oppose the hard-line Sunni Taliban and al Qaeda, back President Hamid Karzai and want stability, reconstruction and an end to drug trafficking. However, the U.S. commander of international forces in Afghanistan, General David McKiernan, this month accused Iran of …