BERLIN (AP) — German Chancellor Angela Merkel has paid tribute to 10 people killed by a neo-Nazi group in an eastern German city where a tree planted in honor of the first victim was recently destroyed.

Merkel on Monday visited a park in Zwickau, where 10 new trees have now been planted in memory of the people, mostly immigrants, killed by the National Socialist Underground group from 2000-2007.

The NSU's only known surviving member was sentenced to life imprisonment last year.

Merkel renewed a pledge that "we will do everything ... so that such things don't happen again."

Last month, an oak tree commemorating the group's first victim, flower seller Enver Simsek, was sawed down.

As Merkel spoke beside the memorial Monday, a handful of far-right protesters nearby chanted for her to leave.