Jewish worshipers in Ukraine were teargassed and the grave of Hasidic Rabbi Nachman of Bratslav was defiled with fake blood and a pig's head in a Wednesday night attack at the popular pilgrimage site visited by tens of thousands of Jews every year.
The incident, at about 2 a.m. in the central city of Uman, was quickly condemned by officials in Israel, with lawmakers calling on Ukrainian authorities to boost security and swiftly seek justice for the perpetrators.
Two Israeli nationals were taken to a local hospital for treatment after the attack, according to Rabbi Yisrael Elhadad, the sexton of the synagogue on the site of the tomb, told Israeli media.
Elhadad described the attackers as neo-Nazis.
"Two of them came in with bottles of paint and sprayed tear gas at worshipers there," he told the Ynet news website.
Pictures of the scene showed blood-like paint spread on floors and walls and a pig's head left nearby.
Police opened an investigation, but no arrests have been announced.
Since the fall of Communism, Uman has seen the arrival of thousands of pilgrims on Rosh Hashanah, the Jewish New Year, who come to visit the gravesite of Rabbi Nachman, the founder of the Bratslav Hasidic sect who died in 1810.
Smaller pilgrimages occur throughout the year and the city has recently seen a rise in Jews moving there permanently.
The pilgrimages have created friction between the predominantly Israeli new arrivals and locals, many of whom resent the cordoning off by police of neighborhoods for the worshipers.
Elhadad said most worshipers were in a smaller synagogue, which was heated, and only five or six people were in the main hall that was attacked.
Israeli Interior Minister Aryeh Deri, head of the ultra-Orthodox Shas Party, said he would contact Ukrainian President Petro Poroshenko to "act swiftly act against the hooligans and increase security."
"I was shocked to the very core to hear of the terrible and barbaric desecration that was done last night at the holy site of Rabbi Nachman from Bratslav," he said according to Channel 2.
The site is guarded, but Elhadad said the attackers were at first thought to be worshipers.
In a letter to Ukrainian envoy Hennadii Nadolenko, MK Yair Lapid, head of the Yesh Atid party, termed the incident a "sickening and violent anti-Semitic attack."
"The event last night had echoes of the darkest days of the Jewish people's history in Europe. Today, we look to your government to immediately condemn this act and use all the power at your disposal to find the perpetrators and bring them swiftly to justice," he wrote.
The chief rabbi of Ukraine told Israel's army radio that vandalism of the grave or attacks against pilgrims are not uncommon.
In September 2015, Ukrainian nationalists destroyed a tent city erected by Hasidic Jews in Uman to lodge visitors ahead of the annual Rosh Hashanah pilgrimage. An eyewitness said at the time the nationalists attacked the tents on Shabbat, the Jewish day of rest, when they knew the pilgrims would not be able to alert police. The damage was estimated at half a million dollars.