Iran's Supreme Leader Ayatollah Ali Khamenei has assailed a two state solution for Israel and the Palestinians, saying the Palestinian bid for statehood at the United Nations is doomed to fail.

Khamenei says the Palestinians should not limit themselves to seeking a country based on the pre-1967 borders — which would implicitly recognize Israel — because "all land belongs to Palestinians."

Khamenei spoke at a pro-Palestinian conference in Tehran on Saturday.

Iran supports the Palestinian Hamas group, which rules Gaza and which does not back the statehood bid pushed by Palestinian President Mahmoud Abbas and his Western-backed Fatah.

Iran doesn't recognize Israel and considers it a top enemy.

Khamenei also called Israel a "cancerous tumor."