BERLIN — The authorities in Hungary came under increasing pressure on Tuesday to take action against a 97-year-old man accused of overseeing a Jewish ghetto during World War II and helping to deport thousands of Jews to Auschwitz.

Efraim Zuroff, who heads the Simon Wiesenthal Center in Jerusalem, said he had informed prosecutors in Budapest last year that the suspect, identified as Laszlo Csatary, was living there and was believed to have played a role in the deportation of 15,700 Jews in the spring of 1944.

Mr. Csatary, who the center says remains fit enough to drive, is also suspected of having served in 1941 as the chief of police and commander of a Jewish ghetto in the city of Kosice, now in eastern Slovakia.

Prosecutors in Budapest said that they had opened an investigation for war crimes against Mr. Csatary in September 2011 but that the shifting of international boundaries and passage of time had slowed the process.

News about Mr. Csatary comes amid international concern over moves by the government of Prime Minister Viktor Orban to introduce laws that have been viewed by its European partners as compromising the independence of democratic institutions, including the judiciary and the news media.

While the government, led by Mr. Orban’s center-right party, Fidesz, has taken steps to meet international demands to revise some of the changes after demands from European Union leaders, there are still concerns over a shift to the right.

At the same time Hungary’s president, Janos Ader, was in Israel on Tuesday for a ceremony at the Knesset to honor Raoul Wallenberg, the Swedish diplomat who saved tens of thousands of Hungarian Jews from perishing in the Holocaust by issuing them with Swedish “protective passports.”

An invitation to the speaker of Hungary’s National Assembly was rescinded after it was learned that he attended a memorial service for an anti-Semitic writer.

In an open letter to the Hungarian president, Mr. Zuroff wrote that the detention of Mr. Csatary could send a strong signal that Hungary remains committed to Europe’s democratic principles.

“One of the most effective ways to combat the rising wave of anti-Semitism, racism and right-wing extremism in Hungary is to bring to justice those who were inspired to commit Holocaust crimes by the same ultranationalism that is once again rearing its ugly head in your country,” he said.

Mr. Ader’s office in Budapest refused to comment on the letter. But Hungary’s opposition Socialist Party has called on the country’s head prosecutor to charge Mr. Csatary “immediately,” and students this week have held demonstrations outside of the building where he is believed to be living.

Also Tuesday, Mr. Orban’s government opened talks with the International Monetary Fund over an agreement for a loan of €15 billion, or $18 billion. Negotiations had been put on hold amid concerns about the independence of the country’s central bank.

nytimes.com