Nir Elias / Reuters

Fans of Beitar Jerusalem shout slogans during a soccer match against Bnei Sakhnin on Sunday amid controversy over Beitar's signing of two Muslim players.

The Beitar Jerusalem club has long been known for its fans' racist chants, but the situation escalated dramatically last month after the team signed Zaur Sadayev and Gabriel Kadiev, two Muslim players from Chechnya.

The most outspoken wave of hate comes from a hardcore section of supporters – known as La Familia -- who see themselves as Beitar’s real owners.

“Death to the Arabs,” they yell during matches. “Beitar, pure forever,” they declare.

Rocks have been thrown at players and, during a recent practice, a fan ran onto the soccer field and tried to attack one of the new Muslim players.

Nir Elias / Reuters

Beitar Jerusalem's new player Gabriel Kadiev, a Muslim player from Chechnya, (right) is seen in action during the game.

The most shocking incident happened on Feb. 8 when the 76-year-old Beitar clubhouse -- home to the club’s trophies -- was burned to the ground. Extremist fans are suspected.

After this, team management and the government decided to take a hard line.

“The police are taking this very seriously,” Jerusalem Mayor Nir Barkat said.  “People who would burn an office are not fans, they are dangerous criminals.”

Abir Sutan / EPA

Meir Harush, one of the board members of the Beitar Jerusalem soccer team, looks over the damage after a fire destroyed the club's history room on Feb. 8. Right-wing extremist fans opposed to a decision by the club owner to sign two Muslim Chechen players are thought to have been responsible.

Bernat Armangue / AP

Burned soccer club trophies won by Beitar Jerusalem are seen after the fire.

Beitar chairman Itzik Kornfein pledged to hold firm too, according to Israeli newspaper Yedioth Ahronot.

“We took an important step and we’re moving forward. In the end, all the fans will understand that this is a done deal and there’s no turning back,” he said, referring to the signing of the Muslim players.

“No turning back” took the form of 400 police officers and 200 private security guards sent to secure a Feb. 10 game between Beitar and the Arab-Israeli club Bnei Sakhnin.

Bernat Armangue / AP

Players Zaur Sadayev, center, and Gabriel Kadiev, background, seen after a press conference, have been subjected to abuse from their own fans.

Despite the security, some Beitar fans hurled abuse about Sadayev and Kadiev as well as the Arab team.

When Kadiev entered the game in the 79th minute, fans from La Familia cursed and booed him, but thousands of other supporters cheered him.

Abir Sultan / EPA

An Israeli fan of Beitar Jerusalem soccer team wearing an Israel flag during the game Sunday.

On the other side, fans from Bnei Sakhnin whistled during the Israeli national anthem.

Two Israeli and three Arab fans were arrested and are awaiting indictment for violent actions during the game.

Abir Sultan / EPA

Muslim supporters of the Hapoel Bnei Sakhnin football team cheer after their team scores in Sunday's game.

Bernat Armangue / AP

Israeli security forces detain Bnei Sakhnin supporters during a game against Beitar Jerusalem on Sunday.

Abir Sultan / EPA

Israeli border police stand guard during the game Sunday.