Thousands of people have taken to the streets in cities and towns across Germany in the latest wave of rallies organized by the new Together for Germany protest alliance, which is demanding tighter border controls and an end to support for Ukraine.

Ahead of the demonstrations on Saturday, which led to several arrests and clashes with counter-protesters, Germany's domestic security agency, the Federal Office for the Protection of the Constitution, warned the populist movement could be hijacked by extremists.

Counter-protesters surrounded Together for Germany rallies across the country, with particularly strong showings in northern urban centers including Berlin and Hamburg where alliance turnout was minimal, according to Deutsche Welle, or DW News.

In Weimar, Thuringia, a stronghold of the far-right Alternative for Germany, or AfD, party, police reported about 1,100 alliance protesters had gathered, with regional far-right extremists among those who made speeches. Around 850 counter-protesters turned out there after a call for action by the local Citizens' Alliance Against the Right.

In Dortmund, one of the alliance's largest gatherings drew 800 supporters but was temporarily surrounded by up to 500 counter-demonstrators.

The pattern of opposition was also evident in southwestern Germany, where Karlsruhe saw 1,200 counterprotesters organized by six different groups and only 200 alliance supporters.

In Koblenz, where 800 anti-fascist protesters outnumbered the alliance's 450 participants, authorities ordered more than 50 people to leave the city center and took 17 into custody, initiating more than 40 criminal proceedings.

Violence marked several demonstrations, with police in Reutlingen reporting "violent attacks on colleagues" from masked left-wing demonstrators.

In Nuremberg, where counterprotesters attempted to block the alliance's gathering through multiple city center blockades, eight officers were injured, forcing police to "repeatedly use direct force, including batons and pepper spray".

The emergence of the Together for Germany alliance reflects a broader trend of rising populist and far-right sentiment in Germany. The movement echoes the ideologies of the AfD, which has gained significant traction, particularly in eastern regions of the country.

The AfD's ascent has been attributed to factors such as economic disparities between eastern and western Germany, historical grievances post-reunification, and growing dissatisfaction with mainstream political parties.

In response to such movements, Germany has seen a wave of pro-democracy demonstrations. In one instance in January this year, up to 1.4 million people opposing far-right movements participated in nationwide protests.

The protests on Saturday followed the alliance's first demonstrations last month, which saw simultaneous rallies across major German cities including Stuttgart, Frankfurt, Munich, Dresden, and Hanover.