BERLIN – Tens of thousands of people gathered in Hamburg on Friday for a demonstration against the far-right, and organizers said the protest ended early because of security concerns.

The event in Germany's second-largest city appeared to be the largest in a growing string of protests over the past week. They follow reports that militants recently met to discuss deporting millions of migrants, including some with German citizenship.

News outlet Corrective last week reported on an alleged far-right meeting in November that it said was attended by figures from the extremist Identity Movement and the far-right Alternative for Germany, or AfD. A prominent member of the identity movement, Austrian citizen Martin Zellner, presented his “immigration” vision of deportation.

Some demonstrations in cities around Germany, including a demonstration in Cologne on Tuesday, have already drawn more participants than expected.

In Hamburg, around 50,000 people gathered on a lakeside promenade on Friday afternoon, while organizers put the number at 80,000, with many unable to enter the venue, German news agency DPA reported.

One of the organizers, Qasim Abasi of the group Unternehmer ohne Grenzen (Businessmen without Borders), said the fire service was unable to get through the crowd, citing security reasons.

“The message for the AfD and its right-wing networks is: We are in the majority, we are strong because we are united, and we are determined not to let our country and our democracy be destroyed for the second time since 1945,” the defeat of Nazi Germany, Hamburg Mayor Peter Tzentscher, told the crowd.

The AfD sought to distance itself from the extremist gathering, saying it had no organizational or financial ties to the event and was not responsible for what was discussed there, saying members who attended did so in a purely personal capacity. However, one of AfD's co-leaders has parted company with an adviser there, while also denying the reporting.

National opinion polls currently show the AfD in second place behind the main centre-right opposition coalition and ahead of the parties in the unpopular government.

More demonstrations against the far-right are planned in German cities over the weekend.