The prime minister of the Hamas administration in the Gaza Strip, Ismail Haniyeh, has arrived in Tehran at the start of a three-day visit.
Iranian state television said Haniyeh was set to meet with Supreme Leader Ayatollah Ali Khamenei and President Mahmud Ahmadinejad for talks on the latest developments in the Middle East.
He is also scheduled to give a speech at ceremonies marking the 33rd anniversary of Iran's 1979 Islamic Revolution on February 11.
Iran, which does not recognize the state of Israel, is a supporter of Hamas but denies providing any financial or military aid to the Palestinian Islamist militia.
Hamas and the Fatah faction of Palestinian Authority President Mahmud Abbas, which runs the West Bank, this week agreed to form a unity government in a deal denounced by Israel.
Compiled from agency reports