(CNN) -- German police on Saturday said no specific attack threat exists, denying a news report that said terrorists may have been planning a strike on the Reichstag parliament building.
"We have no firm lead on a specific location of a potential attack, or names or groups," said Joerg Ziercke, head of the Federal Criminal Police Office.
Der Spiegel, a German weekly magazine, reported earlier Saturday that members and associates of al Qaeda were planning an attack on the Reichstag building in Berlin. The building is home to the country's parliament and also a top tourist destination.
The magazine did not identify its sources, which reportedly said the group would seek to take hostages.
"What Der Spiegel wrote is to be seen and understood in context with the overall assessment of potential targets being possibly highly symbolic places, buildings, venues," said Ziercke. "We investigate some specific persons, but we cannot yet make connections to specific threats on specific locations or type of attacks. Der Spiegel is speculating."
The magazine reported that information about the planned attack came from a "jihadist" who wants to abandon the group. According to the tipster, the terror cell is made up of six people, two of whom are already believed to be in Berlin, Der Spiegel said.
Earlier this week, Interior Minister Thomas de Maiziere said concrete evidence had emerged of a possible attack planned in Germany, but he did not offer specifics.
The United States issued a general travel alert for Americans in Europe last month amid concerns that al Qaeda or related groups might be planning attacks similar to the 2008 massacre in the Indian city of Mumbai.
Ziercke called for calm.
"I want to emphasize: there's no reason for panic or hysteria in Germany. There's also no reason to consider the cancellation of any public event," he said.