The Argentine-born musician is believed to be the first person in the world to possess both passports after receiving his new documentation at the end of a piano concert of Ludwig van Beethoven sonatas, which he performed in Ramallah in the West Bank at the weekend.

"Under the most difficult circumstances he has shown solidarity with the Palestinian people," Mustafa Barghouti, the Palestinian MP and presidential candidate said at the charity concert to raise money for medical aid for children in the Gaza Strip.

Barenboim, 65, who is musical director of the Staatsoper in Berlin and Milan's La Scala opera house, established his West-Eastern Divan orchestra with the American-Palestinian intellectual Edward Said in 1999 following a workshop in Germany. The orchestra's aim is to bring together musicians from Israel and Arabic countries to exchange ideas and perform together.

Barenboim, who is a regular and lively commentator on the Middle East conflict, said he was "moved and very, very happy" to receive the citizenship, adding that he accepted it because it "symbolises the everlasting bond between the Israeli and Palestinian people".

In a pointed reference to US president George Bush's recent comments on the Middle-East conflict in which he talked of Israel's "occupation" of the West Bank, Barenboim added: "Now even not very intelligent people are saying that the occupation has to be stopped."

Barenboim is considered a controversial figure by many in Israel, but less for the sympathy he openly shows towards the Palestinians and more for his promotion of the music of the 19th century anti-Semitic German composer Richard Wagner which he has conducted in Jerusalem.

He criticised the Israeli government after he was forced to cancel a piano concert in Ramallah after Israeli authorities said they could not guarantee his safety. More recently he held a press conference to protest the Israeli authorities' refusal to allow musicians from his Divan orchestra to enter Ramallah.