Chancellor Angela Merkel expressed reserve Wednesday at the notion that Barack Obama could use the backdrop of Berlin's Brandenburg Gate to promote his bid to become the next president of the United States, reported dpa.
Although the Illinois senator, who is expected in the German capital on July 24, has not yet put in a request for the venue, the pending visit has drawn widespread comment in Germany.
Merkel felt a "certain unease" at the idea, government spokesman Thomas Steg said, noting, however, that the decision lay in any case with the city authorities and not with the federal government.
Merkel's deputy, Foreign Minister Frank-Walter Steinmeier, had no difficulty with the idea, his spokesman said.
Berlin Mayor Klaus Wowereit has backed the notion, while adding that he would also extend a welcome to John McCain, Obama's Republican Party rival in the presidential race.
Both Steinmeier and Wowereit are members of Germany's Social Democratic Party (SPD), which is traditionally close to the US Democrats, while Merkel's Christian Democrats (CDU) are seen as closer to the Republicans.
Berlin authorities said earlier this week they were expecting Obama, fuelling earlier speculation that the Illinois senator could use the venue to make a major speech on changes in US policy towards Europe should he be elected.
German media reports have suggested the speech could pledge greater US cooperation with Europe, while at the same time calling for a greater contribution in Afghanistan and Iraq.
The venue has strong historical overtones for US-German relations. Former presidents Ronald Reagan and Bill Clinton made key speeches here while in office.
It was here that in 1987 Reagan urged the Soviet Union's last communist leader: "Mr Gorbachev, open this gate! Mr Gorbachev, tear down this wall!"
A little more than two years later, the wall did in fact come down.
In 1994, Clinton ended a speech at the same site with the words: "Berlin ist frei" (Berlin is free).
Berlin was the venue for another famous speech by a former US president.
John F Kennedy made his famous "Ich bin ein Berliner" (I am a Berliner) in 1963, less than two years after the wall went up, although he was speaking not at the Brandenburg Gate but on the steps of a large city hall not far away.
The Obama campaign team is said to hope that "television pictures of 100,000 cheering supporters" listening to the senator in Berlin would boost his election chances by showing that relations with Europe would improve under an Obama presidency.
German leaders could also benefit from being seen with the charismatic senator. The next German parliamentary elections are in September next year.
A weekend poll showed that 72 per cent of Germans would vote for Obama if they had the chance, against just 11 per cent for McCain.