Guillermo Zapata , a member of the Ahora Madrid party, tweeted in 2011: "How do you get five million Jews in a (Seat) 600? In the ashtray."
According to The Spanish Report website, Zapata was tipped to receive the capital’s culture portfolio. The Spanish media reported that Zapata apologized for the tweet, denying that he was anti-Semitic, and conceding that politicians should know better.
He said, according to the reports, that he had "always liked black, cruel humor."
"I find the Holocaust to be deplorable and terrible," Zapata said in his apology on Twitter. "I am absolutely not an anti-Semite, on the contrary, I have always been interested in Jewish culture and have always been against the criminalization of the Jews."
The Socialist Party, which struck a deal with Ahora Madrid to take power of the city municipality after decades of conservative control, demanded an immediate explanation from the mayor’s office, El Mundo said.
"The city of Madrid cannot tolerate any racist attitudes and should have a zero tolerance approach to xenophobia," said Socialist Party spokesman Antonio Miguel Carmona. He also demanded Zapata’s resignation.
Zapata deleted his old Twitter account @casiopeaexpres almost as soon as the old tweet resurfaced, and opened a new one with the similar handle of @casiopeaexpres_.