Free Democratic Party Bundestag Member Burkhard Muller-Sonksen was being booed while speaking at a rally Saturday when a protester climbed onto the speaker truck, grabbed his microphone and shoved him to the floor, a spokeswoman for alliance that organized the protest told Die Welt.
The Hamburg event was one of a series of protests in cities such as Frankfurt, Munich, Berlin and Karlsruhe that drew hundreds of angry residents who denounced reports Germany is a "key partner" with the U.S. National Security Agency in its PRISM digital anti-terrorism surveillance program.
Politicians of all parties -- including the Greens, Social Democrats and the government coalition partner FDP -- were booed at the events and accused of collaborating with Chancellor Angela Merkel's Christian Democratic Union-led government on the NSA program revealed by fugitive former U.S. national security contractor Edward Snowden, German press reports said.
The Hamburg event was organized by Germany's Pirate Party and the Chaos Computer Club hacker group, which advocates freedom of information.
Anti-spying alliance speaker January Girlich said the FDP politician was shaken up by the attack.
"Muller-Sonksen was shocked and surprised," she told Die Welt. "The Chaos Computer Club condemns violence and calls for peaceful protest."
The regional broadcaster Norddeutscher Rundfunk reported Muller-Sonksen had been addressing a rally attended by 2,000-3,000 protesters, denouncing the surveillance, but was still booed before the incident, possibly due to the role of his party in the German government.
Amid sweltering 95-degree heat, protesters carrying signs reading "Stop Watching Us!" began a march near Hamburg's Central Station and later moved to the Reeperbahn, where a final rally was held. Organizers put the attendance at 3,000, while police reported 2,000.
In Frankfurt, where 5,000 protesters were expected, police said only 1,000 people attended, while organizers put the number at around 4,000.
At that event, Hesse FDP state leader Jorg-Uwe Hahn, Wiesbaden Green Party Chairman Tarek Al-Wazir and the Left Party leader Janine Wissler were all subjected to persistent catcalls and boos, Die Welt reported.
Even the Green Party's Al-Wazir was heckled, despite calling for an end to massive government data collection.
"We need to have more courage to defend ourselves against these monitorings," he said, calling for the exchange of information between Germany and the United States to be terminated and renegotiated.
Nevertheless, he was greeted by calls of "Liar!" and "Hypocrite!" from the crowd, the newspaper said.
The German information technology news website Golem.de reported a march in Munich was held between the U.S. Embassy and the America House, a symbol of the post-war U.S. friendship with Bavaria.
Florian Ritter, SPD parliamentary spokesman in the Bavarian state parliament, denounced the NSA program and said such comprehensive surveillance was "illegal and unconstitutional," the website reported.
Glenn Greenwald of the British newspaper The Guardian told Der Spiegel this month information obtained by Snowden about the expansive NSA cellphone and Internet surveillance programs would be "more explosive in Germany" than previous reports about cooperation between the NSA and German intelligence.
During an interview with German public radio, Greenwald said Germany wasn't working with the United States on the same level as Britain, Australia, Canada or New Zealand, but it was "sort of in the next tier where they exchange information all the time."