Police said two of 11 colorful wooden benches placed on Zwickau's Schumann Square only last Friday by artists and engraved with the names of each NSU victim vanished on Monday night - despite being affixed with cables and screws.

Zwickau was also famed as the birthplace in 1810 of the acclaimed composer Robert Schumann.

In Chemnitz, another city in the state of Saxony, police said a pyrotechnics device had wrecked a window at the cultural center "Lokomov," which is currently hosting a theater production "Unentdeckte Nachbarn" (Undiscovered Neighbors).

'Undescribable grief'

On its website, the Zwickau artists' group "Sternendekorateure" (Star Decorators) said it was determined to show that hatred would not win over Germany's constitutional principles, especially in "our home city of Zwickau, where persons resided who brought indescribable grief to many other families."

Zwickau was in 2011 the home of two NSU suspects, Uwe Böhnhardt and Uwe Mundlos, the presumed murderers of nine residents and a policewoman between 2001 and 2007, most of whom were of Turkish origin.

Böhnhardt and Mundlos died in an apparent murder-suicide after a bank robbery in Eisenach on November 4, 2011.

A third suspect, their Zwickau flatmate Beate Zschäpe, is still on trial in Munich.

"We repair wooden furnishings, we remove painted smears, we will continue to provide for a dignified commemoration," the Sternendekorateure wrote Tuesday, saying some wooden benches had already been defaced with white paint over the weekend.

"And it's worthwhile: Today someone unknown laid a rose on each of the remaining benches."

Numerous parliamentary inquires are still underway into why it took authorities four years to link the NSU to the past murders, bombings and robberies.

Intimidation also in Chemnitz

The manager of Chemnitz's "Lokomov" center Lars Fassmann on Tuesday put the damage from Monday night's defacement at 2,500 euros ($2,755 US) and said it represented a new scale of violence.

Neonazis had previously beaten up visitors who had attending events at the center, he told the German news agency DPA.

Chemitz opposition Greens party politician Petra Zais described Monday's detonation as a "sad highpoint in a whole series of attacks on institutions that campaign against right-wing extremism."

Cologne to erect memorial

In Cologne, where the NSU staged bombings in 2001 and 2004, injuring some 20 people, city authorities are preparing to erect yet another memorial to NSU victims.

In October last year, Cologne's then-future mayor, Henriette Reker, survived a knifing by a 44-year-old man who said he objected to pro-refugee policies espoused by Reker and Chancellor Angela Merkel.

That assailant was subsequently jailed for 14 years.

At the Munich trial, now into its fourth year, Zchäpe faces charges of being an accessory to the racist-motivated murders as well as setting fire to their Zwickau apartment in which the trio had lived.

ipj/kl (epd, dpa, AFD)