BUDAPEST, Hungary — Russia's president said Tuesday he is optimistic that his country will strike an agreement with Iran over its disputed nuclear program.

A delegation led by top Iranian negotiator Ali Larijani is expected to arrive in Moscow today for discussions on a Kremlin proposal to enrich uranium for Iran on Russian territory to ensure the nuclear fuel cannot be diverted for atomic bombs. Enrichment is a process that can produce fuel for a nuclear reactor or fissile material for a weapon.

"We are optimists," Vladimir Putin told reporters on a visit to Hungary. "It's quite possible for us to reach an agreement on the establishment of a joint venture for Iranian nuclear energy needs."

The negotiations remain hamstrung over Iran's refusal to restore a freeze on its domestic uranium activities — a condition that Moscow says is essential for its plan.

Iran's foreign minister said today that his country will be flexible in talks with Moscow.