Tehran, Jan 17 (IANS): Iran's Supreme Leader Ayatollah Ali Khamenei said here on Tuesday that Jerusalem is "definitely" the capital of Palestine.

The US move to call Al-Quds (Jerusalem) the capital of Israel will fail eventually and "they won't be able to implement this (decision)", Khamenei said at the 13th session of the Parliamentary Union of the Organisation of Islamic Cooperation in Iran's capital Tehran.

He said the governments who help the US and Israel are "traitors to Islam and Muslims", Xinhua news reported.

He added that the cause of Palestine is the foremost issue of the Muslims.

The cause of "Palestine is an important issue of Islamic world and should not be forgotten", he was quoted as saying by semi-official ISNA news agency.

The resistance against the Israeli occupation of the Palestinian territories has achieved advancements so far and "I believe that it will bear fruit", he said.

Khamenei also urged unity and solidarity among Islamic countries.

Last December, US President Donald Trump announced his recognition of Jerusalem as Israel's capital, and instructed the State Department to begin the process of moving the US Embassy from Tel Aviv to the holy city.

Iran's Foreign Ministry strongly condemned the decision, saying Washington's recognition was a "blatant violation of international resolutions".