An altercation between several Israelis on a HelloJets flight to Bucharest escalated to a massive fight involving some 30 passengers on Sunday night, according to Romanian media.

HelloJets was operating the flight for Israel’s Israir, which confirmed the incident, but said that 11 people were involved.

Romanian publication Mediafax reported that the border police was notified ahead of the flight’s arrival at Henri Coandă International Airport that their presence was required as soon as the plane landed.

The border police told Mediafax that the cause was a “spontaneous conflict” that broke out between several Israeli passengers, without giving further details.

Upon arrival of the flight, the border police investigated the incident with the flight crew, according to Romanian newspaper Adevărul, before identifying the Israeli passengers they believed to be directly involved in the fight.

The passengers were escorted from the plane for further investigation and were fined 4,000 Romanian Leu ($930) each, the publication added.

Israir, which hired HelloJets to operate its flight to Bucharest, told Ynet in response to a request for comment that the incident had involved 11 passengers.

“Israir condemns violence of any kind and operates according to law and regulations,” the airline added.