WARSAW (Reuters) - Poland’s ambassador to Israel was spat at while sitting in his car in Tel Aviv, Israeli police said, drawing condemnation from the Polish government at a time of rising tensions between the two countries.

FILE PHOTO: Polish Prime Minister Mateusz Morawiecki arrives at a summit of the Visegrad Group of central European nations and Japan in Bratislava, Slovakia, April 25, 2019. REUTERS/Radovan Stoklasa/File Photo

An Israeli police spokesman said on Wednesday a 65-year-old Israeli architect was arrested over Tuesday’s spitting incident. At a court hearing on Wednesday, he was put under house arrest until police complete their investigation, his lawyer said.

“The event is under police investigation. We express our fullest sympathy to the ambassador and our shock at the attack,” Israeli Foreign Ministry spokesman Emmanuel Nahshon said.

The Polish Foreign Ministry summoned Israel’s ambassador to Warsaw, Anna Azari, over the matter, a ministry spokeswoman told the state-run news agency PAP.

“I am very worried to hear of a racist attack on @PLinIsrael ambassador @mmagierowski. Poland strongly condemns this xenophobic act of aggression. Violence against diplomats or any other citizens should never be tolerated,” Polish Prime Minister Mateusz Morawiecki wrote in a tweet.

Polish-Israeli relations have deteriorated in recent months over accusations that Warsaw’s nationalist PiS government has tolerated a revival of anti-Semitic behavior, a charge it denies.

Hundreds of far-right supporters marched in Warsaw on Saturday in protest against a U.S. law on the restitution of Jewish property seized during or after World War Two, an increasingly prominent issue in Polish election campaigns.

David Johan, the suspect’s lawyer, told reporters his client had been turned away from the Polish Embassy on Tuesday after trying to inquire about restitution.

Later, outside the embassy, the alleged assailant “approached the vehicle of the Polish ambassador to Israel, opened the door and then spat (at him),” police spokesman Micky Rosenfeld said.

Johan said the assault was not premeditated, adding: “My client was walking in the street and an embassy vehicle honked at him.”

In a statement issued to reporters, the suspect, Erik Lederman, said his family had been through the Nazi Holocaust and that a Polish embassy employee had used an anti-Semitic slur against him while he was there, which he found upsetting.

“I did not know that Poland’s ambassador was in the car. Consequently, I would like to express my sincere apology for what happened,” Lederman said.

Poland’s Ambassador to Israel Marek Magierowski denied in a post on Twitter that there had been any inappropriate behavior or language used by embassy employees.

The PiS government has said that Poland - which had one of the world’s biggest Jewish communities before it was almost entirely wiped out by Nazi occupiers - was a victim of World War Two and so should not be saddled with any financial obligations.

In response to the ultra-nationalist march, the World Jewish Congress urged Polish religious and political leaders on Wednesday to unequivocally condemn anti-Semitism.

On Monday the Polish government canceled a visit by an Israeli delegation as it learned that the Israelis intended to bring up the restitution issue, the Foreign Ministry said.