A group of South Koreans visiting North Korea’s Mount Geumgang was briefly detained Sunday for allegedly making unauthorized contact with a soldier from the communist state.

According to the Hyundai Asan Corporation, the organizer of the tour, around one-thousand tourists were detained for some 40 minutes after Grand National Party Rep. Cha Myung-jin offered snacks to a North Korean soldier standing guarding.

Cha was part of the group visiting North’s scenic mountain resort to attend an ground-breaking ceremony for a coal briquette factory.

Shortly after being released, the group returned home late Sunday afternoon.

Travelers are prohibited from making contact with North Korean guards and residents at the resort, which has been open to tourists since 1998.