Adidas has banned football fans from buying German football kits customised with the number 44, after media raised their resemblance to the symbol used by World War Two-era Nazi SS units.
"We will block personalization of the jerseys," an Adidas spokesman said.
SS units were the most responsible for the crimes against humanity committed by the Nazis.
The newly released kit has also caused controversy with its choice of pink for the away colours.
The symbolism issue was first raised by historian Michael König, who said the design of the kits was "very questionable".
The SS rune was designed in 1929 for use by the Nazi units. Members of the SS ranged from Gestapo agents to concentration camp guards. SS duties included administering death camps where millions of Jews and others were put to death.
Adidas spokesman Oliver Brüggen denied that the kit's resemblance to the Nazi symbols was intentional.
"We as a company are committed to opposing xenophobia, anti-Semitism, violence and hatred in every form," he said.
Adidas separately told the BBC that the German Football Association (DFB) and its partners had designed the numbers on the shirts.
In a post on Twitter/X, the DFB said the shirt designs had been submitted to UEFA for review during the design process and that "none of the parties involved saw any proximity to Nazi symbolism".
They added that an alternative design for the number 4 would be developed.
The same kit has met additional controversy for its choice of bright pink as the away colour. Supporters say the colour represents the country's diversity. But critics claim it is untraditional and has been introduced in order to raise money for the DFB.
Adidas has manufactured German jerseys since the 1950s.
But a decision by the DFB to drop German company Adidas in favour of American giant Nike as the manufacturer of German football kits from 2027 has been blasted for lacking "patriotism" by Economy Minister Robert Habeck.
Germany will host this year's European Football Championship, which will be held in 10 different cities.