US President Barack Obama has visited the Buchenwald concentration camp in central Germany. Together with Chancellor Angela Merkel he paid tribute to the millions op people killed by the Nazis before and during World War II.

A number of survivors were also present at the ceremony. Prior to the visit, Mr Obama urged Iran's President Mahmoud Ahmadinejad to see Buchenwald for himself. The Iranian leader has denied that the Holocaust claimed the lives of six million Jews.

The US president reiterated he would redouble his efforts to achieve a lasting peace in the Middle East. On Thursday, he was in the Egyptian capital Cairo, where he had given a long-awaited speech to the Muslim world. On Saturday, Mr Obama will attend a commemoration of the D-Day landings in Normandy, which marked the beginning of the end of the war.