U.S. Democratic presidential candidate Barack Obama made a surprise pre-dawn visit to Jerusalem's Western Wall on Thursday, at the end of a trip aimed at showing his strong support for Israel.

Obama, wearing a Jewish skullcap, placed a prayer he had written in the wall and bowed his head while a rabbi read a psalm calling for peace in the holy city.

One worshipper chanted "Obama, Jerusalem is not for sale" and "Jerusalem is our land" as the Illinois senator stood at the wall, a relic of the ancient Jewish temple destroyed during Roman rule nearly 2,000 years ago.

Obama assured Israel and its U.S. Jewish supporters on Wednesday he was a friend who would not press for concessions in peace talks with Palestinians that would compromise its security.

Hailing Israel as a "miracle", he vowed staunch support and held only a low-profile meeting with Palestinian leaders in the occupied West Bank.

Last month Obama dismayed Palestinians when he said Jerusalem must be Israel's "undivided" capital. Israel captured Arab East Jerusalem in 1967, including the Old City where the Western Wall is situated, but Palestinians want it to be the capital of a future state.

Obama later said he had used "poor phrasing".

He is due to fly on Thursday to Germany, where he will give the only public speech of his week-long foreign tour, an outdoor address on transatlantic ties that is likely to draw tens of thousands.

Highly popular in Germany, where he is often likened to former U.S. President John F. Kennedy, Obama will also meet for the first time Chancellor Angela Merkel, who opposed his initial plan to speak at the Brandenburg Gate.

Instead, Obama will give his evening address at the "Victory Column" in Berlin's central Tiergarten park, down the road but still within sight of the Gate, a landmark that stood behind the Berlin Wall for decades as a potent symbol of the Cold War.