At least 40 Israeli citizens were briefly detained upon landing in Moscow from Tel Aviv before being released, Israel’s Foreign Ministry confirmed Monday evening, the Times of Israel reports.

“Immediately upon learning of the incident, at the instruction of Foreign Minister Gideon Sa’ar, the Foreign Ministry acted both with the foreign ministry in Moscow and with the Russian embassy in Israel,” the ministry says in a statement.

“Following this intervention, the incident was resolved and the Israelis’ entry was approved. The Russians were made to understand that this conduct is completely unacceptable, and Israel views the incident with great seriousness,” the ministry adds.

While officials declined to provide further specifics, a source familiar with the situation told independent Russian outlet Mediazone that the travelers were questioned by Russian security personnel over suspected links to Israel’s war with Iran, and were held for approximately five hours without access to food, water, or restrooms.

According to the report, those detained included both dual nationals and Israelis without Russian citizenship, and were required to unlock their phones during the questioning. Security officers reportedly told them that Iran is considered an ally of Russia and warned that anyone viewed as an enemy of Iran is “our enemy as well.”

The group was ultimately released after being made to sign documents affirming the “inadmissibility of violating the law” and cautioning against future infractions, the report said.