All seven Israeli chess players withdrew on Thursday from an international chess tournament in Spain, following a series of harassing incidents by the event’s organizers.

The Sestao Chess Club, which is hosting the 40th Basque Country Open in Sestao, northern Spain, on Sept. 12-18, sought to remove the Israeli national flag from the tournament, welcomed local organization’s pro-Palestinian protests, and, a day before the competition started, informed the Israeli players they would have to lodge in another city.

“One after another they kept pulling out and finally the last one, this very morning, decided not to come,” said Miguel Ángel del Olmo, president of the Sestao Chess Club, according to Reuters.

“We have acted in accordance with international regulations, but we invited them not to take part and we thank them for their decision,” he added.

Speaking of local rallies planned to protest against Israel on Sept. 13, del Olmo was quoted as saying that he supported their message against “genocide” in Gaza.

The Israelis withdrew from the tournament after the Sestao Chess Club decided to remove all national flags from the tournament’s grounds—but not the Palestinian flag.

Initially, the organizers attempted to remove only the Israeli flag, but the International Chess Federation (FIDE) prevented the move, which violated the federation’s regulations.

“FIDE had no prior knowledge of this decision, did not make any ruling on this, nor was it consulted by the organizers. FIDE strongly condemns any form of discrimination, including on the basis of nationality and flag,” it said in a statement last week, Reuters reported.

On Thursday, the Israeli players received a message from the organizers that their safety cannot be guaranteed, according to Israel Hayom.

“In light of the impossible situation and the lack of choice left by the organizers, the Israeli chess players unanimously decided not to participate. The risk to their safety and well-being, when the organizers not only fail to ensure their security but also encourage protests during the tournament days, is a disgrace to the game of chess and to sports in general,” said Lior Aizenberg, who represents the players, the report continued.

“Using the competition as a tool to delegitimize Israel, encourage antisemitism and incite hatred constitutes a severe breach of every proper public norm for organizing sporting events. This case is exceptional and requires sanctions against the organizers and all participants in this conspiracy,” Aizenberg added.

He vowed to bring the matter before legal authorities and said he would work to ensure that the Israeli players are compensated for their damages, according to outlet Walla News. He added that he will act to ensure that “such an exceptional situation will not happen again in the future.”

In a Facebook post on Friday, Aizenberg slammed the president of the competition, saying he “shouldn’t organize any single chess event in his life, and the chess tournament in Sestao shouldn’t be rated!” that is count for players’ FIDE ratings.

In a separate post on Saturday, he wrote: “Israel-hatred has reached a new record. The Spanish organizers removed all national flags—including Spain’s own flag—and replaced them with regional flags and the Palestinian flag. A ‘country’ that doesn’t even exist, with not a single player in the tournament. The absurdity knows no limits.”

The Sestao event has drawn more than 250 players from 33 countries.