Dortmund coach Juergen Klopp and former Germany star Lars Ricken on Friday called for an end to the slaughter of stray dogs by Euro 2012 co-hosts Ukraine.
The two men posed for a photograph to denounce "these massive and cruel slaughters," said Ricken, who retired in 2009.
"It's not about boycotting the Euro but to have a humane attitude towards all living things."
The pair believe neutering strays would be the best long term solution.
Some 300 animal rights activists, brandishing banners "football does not need blood" and "yes to neutering, no to murder", last month called for the championship to be boycotted if the Ukraine continued to slaughter dogs ahead of Euro 2012.
Ukraine and Poland co-host the tournament from June 8 to July 1.