Members of the Israel Defense Forces’ elite counterterrorism and canine units performed drills on Tuesday for the guests of a bat-mitzvah party at the Adam base, near Modi’in. The party was held by a New York businessman, a veteran donor to various IDF units.

Military sources told Haaretz the event was not a bat-mitzvah party, rather a tribute by the unnamed donor and his family to the base’s soldiers. The sources said that in the course of the event it was mentioned that one of the family members had reached the age for the ritual.

But soldiers who attended the event said six or seven busloads of civilian guests were brought to the event. One soldier estimated the cost of the festivities, which included fireworks, a performance by popular Israeli singer Moshe Peretz and a catered dinner, at around 1.5 million shekels ($438,000).

On Tuesday evening, soldiers serving in the counterterrorism and Oketz (elite canine forces) units were instructed to prepare for a briefing. They assumed it would be related to Operation Brother’s Keeper, the IDF operation that is now focused on finding the perpetrators of the kidnapping-murder in June of three Israeli teens in the West Bank. Instead, they discovered they were to demonstrate their abilities before an audience of a few hundred civilians.

The demonstration included pyrotechnics and exercises with the Oketz dogs, and was projected onto giant screens for the benefit of the guests. A number of unit commanders, as well as members of the benefactor’s family, gave speeches.

According to soldiers who attended the briefing, they were prohibited from bringing cellphones to the evening’s festivities or reporting them on social media. One soldier said they were warned that anyone caught with a cellphone in the facility would be jailed. Participating soldiers had their hands stamped in order to exclude anyone who had not been vetted from the area where the party was held.

Photographs obtained by Haaretz suggest that lavish sums were spent on the event. A compound with stages, food counters and lounges was built, and special lighting was installed. The affair was held in the counterterrorism unit’s training area, adjacent to the unit’s firing range and not far from the munitions depot. A number of soldiers were reassigned in order to help prepare for the event.

A former officer from the counterterrorism unit said Tuesday’s event was not the first of its kind, albeit it was unusually lavish. “The idea is to let [donors] party with soldiers, including some kind of military drill, so they’ll give the unit money,” he said.

A military source said the donor’s family had been contributing money to the IDF for many years and hosts a party with live entertainment and catered food for soldiers on a different base every year. A year ago, for example, the family underwrote dinner and a show and food at the Tel Nof base. “It was an event for the soldiers, a tribute to them. Only 10 family members attended the event,” the military source said.

In a statement, the IDF spokesman said a preliminary investigation suggests the decision to hold the event, which was scheduled far in advance, on Tuesday was “based on erroneous judgment.” He said the matter would be examined and any necessary action would be taken.