WARSAW, Poland (AP) — Police in northern Poland are facing questions over why they released without detailed interrogation three divers rescued from near a key oil port, where they had no authorization to be.

Security experts say the presence of the divers in the sensitive area of the Gulf of Gdansk last weekend raised concerns, given the high tensions with Russia over its energy deliveries. The divers had Spanish identity documents.

According to Polish media, the divers were rescued early Sunday after they sent a distress message when their unregistered small boat malfunctioned in stormy weather.

They were equipped with professional diving gear and claimed they were looking for amber, but none was found in the boat. They had no permission to dive in the gulf.

Despite a high level of security introduced across Poland due to the country's support for Ukraine in its war with Russia, police released the men. That has raised questions, the more so because the phone numbers they gave turned out to be inactive.

In raising their concerns, experts are pointing to the underwater explosions last summer that damaged the Nord Stream 2 pipelines that run on the Baltic Sea bed and were to carry Russian gas to Germany. Swedish and Danish authorities have said the leaks were sabotage.