AFP - Iranian supreme leader Ayatollah Ali Khamenei told Palestinian militant chiefs on Saturday that sustained resistance was the key to liberating their land.

"Palestine, surely and definitely, will be freed by sustained resistance from the people of Palestine and by maintaining unity among jihadist groups," Khamenei said.

He met Hamas political leader Khaled Meshaal, Islamic Jihad leader Ramadan Abdullah, and the head of the Popular Front for the Liberation of Palestine - General Command (PFLP-GC) Ahmed Jibril, all of whom live in exile.

Khamenei said that "supporters of the Zionist regime will have nothing but shame and a bad name in history."

The three militant leaders are attending a conference organised by Iran in support of the Palestinians. Iran does not recognise Israel and is a staunch backer of Palestinian militant groups.

Tensions have soared between Iran and Israel since hardline President Mahmoud Ahmadinejad came to power in 2005.

Ahmadinejad has drawn international condemnation by predicting that Israel is doomed to disappear and dismissing the Holocaust as a "myth," while Israel has refused to rule out military action to prevent Iran developing a nuclear bomb.