The office of a controversial anti-immigration politician from Chancellor Angela Merkel's Christian Democratic Party was vandalized overnight, police in the eastern city of Leipzig said on Tuesday.

The unknown attackers smeared the outside of the office with a black substance, smashed in four windows and trashed the inside of Bettina Kudla's office in Leipzig, police said.

Kudla recently used the word "Umvolkung," meaning "ethnicity inversion" in a tweet about immigration.

The world was originally used by the Nazis to refer to the forced ethnic change of a population by immigration or compulsory transfer in Eastern Europe.

It was also used to refer to the Germanization or re-Germanization of eastern occupied areas in World War Two. The term has recently been used by the right-wing to criticize Germany's intake of migrants and refugees.

"The ethnicity inversion of Germany began long ago. It's time for action!" Kudla wrote in the tweet criticizing Germany's immigration policy.

CDU politicians and others condemned the tweet.

Left-wing violence

"MDR Sachsen" news reported that as early as Sunday a post published on left-wing, anti-fascist website "linksunten.indymedia" claimed responsibility for the attack on Kudla's office.

According to the claim of responsibility, as a member of parliament Kudla was responsible for the hardening of asylum policies and the worsening of basic unemployment insurance. She was also the only member of parliament to vote against the Armenian genocide resolution earlier this year "in order to not put in danger the dirty refugee deal between the EU and Turkey," the claim said.

Kudla's office was also attacked in August. A claim for that attack was also posted on "linksunten.indymedia."

The vandalism comes after a series of attacks on offices, vehicles and election posters of the anti-immigration Alternative for Germany party, support for which has risen to double-digits.

The influx of migrants in Germany has led to an increase xenophobic right-wing attacks on migrants and refugees, but there has also been increased concern over left-wing violence against the right-wing.

According to government statistics, there were more than 800 attacks directed at public servants, including local politicians, since the start of the year. Most were committed by right-wing extremists.

cw/kl (dpa)