Poland’s Ministry of Foreign Affairs said that British Holocaust denier David Irving is not welcome to visit Poland.

Irving is taking deposits on his website for the tour of Nazi historical sites scheduled for September, including visits to the sites of the Nazi death camps Treblinka, Belzec, Sobibor and Majdanek.

“British Holocaust denier David Irving probably will not be able to enter Poland due to the fact that his opinions are unacceptable from the point of view of Polish law,” Foreign Minister Jacek Czaputowicz said at a news conference on Friday.

Irving is planning to spend nine days in Poland in September. In addition to the former Nazi death camps, he plans to visit the bunker headquarters of Adolf Hitler known as “The Wolf’s Lair” and the headquarters of SS chief Heinrich Himmler. Similar trips took place in 2013 and 2010.

Czaputowicz said that the Polish government had “already taken some steps” to prevent Irving from entering the country.