(CNN) Chess tournaments, for better or worse, don't usually command international headlines.
But that hasn't proved true for the World Chess Championships in Riyadh, Saudi Arabia, which has become the focus of debates this week on Israeli-Saudi relations and women's rights in the country.
On Saturday, one of the best women's chess players in the world, Anna Muzychuk of Ukraine, said she and her sister would skip the tournament as a protest of the country's treatment of women as "secondary creature(s)."
Separately, Israeli officials criticized Saudi Arabia and the World Chess Federation, known as FIDE, on Tuesday after seven Israeli competitors were not granted visas to attend the tournament.
"Sports and competition should serve as a bridge between groups and nations," Jonathan Greenblatt, CEO of the Anti-Defamation League, said in a statement.
"It is an accepted principle in competitive sports -- and part of FIDE regulations -- that hosts of international competitions must permit all competitors to participate. The Saudi refusal to provide visas to the Israeli team is a violation of this principle and a violation of sportsmanship."
The World Chess Championships is one of the largest chess tournaments of the year, with a total prize money of $2 million, according to FIDE.
Saudi Arabia and FIDE agreed to loosen the dress code for the event and allow women to wear high-necked white blouses rather than a hijab or abaya, a loose-fitting robe worn by some Muslim women. That dress code was a first for any sporting event in Saudi Arabia, the organization said.
FIDE also said that it had made "ground-breaking special arrangements" to issue visas to chess players from Iran and Qatar, two countries at odds with Saudi Arabia politically. The statement did not mention Israel, however.
"As everybody clearly understands from the above, FIDE and the Saudi organisers are always ready to welcome any participant," FIDE said. "FIDE's principle is that its World Chess Championships are a vehicle for promoting peace and development of friendship amongst all nations."
But Zvika Barkai, the Chairman of The Israeli Chess Federation, said that statement was "not only an insult to simple logic but also a shame for FIDE."
Barkai particularly took aim at FIDE claiming to welcome "any participant" even as it did not allow Israeli chess players to attend.
"This sentence means that in the eyes of FIDE Israeli players are not included in the list of 'any participant,'" Barkai said.
Barkai called on FIDE to cancel the contract with Saudi Arabia for next year's chess tournament, to compensate Israel players who were denied visas and to declare that this will not happen again.
Greenblatt said FIDE officials did refer to the boycott of Israeli athletes at the opening ceremony, but called on them to do more.
"While FIDE officials did refer to the boycott of Israeli athletes in the opening ceremony today, as the sponsoring body FIDE should make clear to the Saudi hosts that it will not be complicit with discrimination against or a boycott of any team regardless of its national origin," Greenblatt said. "FIDE must send a message that if Saudi Arabia continues with this policy, it will not be eligible to host future championships."
The spokeswoman for the Saudi embassy in the US, Fatimah S. Baeshen, defended the decision on Twitter.
"The Kingdom has allowed the participation of all citizens. The exception is whereby (Kingdom of Saudi Arabia) has historically not had diplomatic ties with a specific country - thus has maintained its policy," she said.
Israel's fraught relationships with its Middle East neighbors have sometimes brought repercussions for its athletes. At the 2016 Olympics in Brazil, Egypt's Islam El Shehaby lost to Israel's Or Sasson in the judo competition and then declined to shake his hand after the match, garnering boos from the crowd. And in 2009, Israeli tennis player Shahar Peer was denied a visa to play in a tournament in Dubai.
Muzychuk, one of the world's top women's players, said in a statement that she would forego the tournament on principle.
"In a few days I am going to lose two World Champion titles - one by one. Just because I decided not to go to Saudi Arabia," the 27-year-old wrote. "Not to play by someone's rules, not to wear abaya, not to be accompanied getting outside, and altogether not to feel myself a secondary creature."
Muzychuk won the Women's World Rapid Championship and the Women's Blitz World Championship in Doha, Qatar last year.
"Exactly one year ago I won these two titles and was about the happiest person in the chess world but this time I feel really bad. I am ready to stand for my principles and skip the event, where in five days I was expected to earn more than I do in a dozen of events combined," she said.
Muzychuk's sister, Mariya, is also a top chess player and will skip the tournament as well, Muzychuk said.
China's Yifan Hou, the top-rated women's chess player, will also not be attending the tournament due to other commitments.
In 2016, Saudi Arabia's grand mufti, the nation's top religious cleric, issued a ban on chess in 2016 because it is a form of gambling, he said. Sheikh Abdul Aziz bin-Abdullah al-Sheikh also called chess "a waste of time, money and a reason for the enmity between players."
Correction: This story has been republished with the correct first name of the CEO of the Anti-Defamation League. It is Jonathan.