The alarm could be heard bellowing in the early hours of Thursday, July 30, as reports circulated on social media that a missile may have crossed into Poland.

Officials have not confirmed whether a missile had entered the airspace.

Videos posted to social media captured the dark sky as the eery signal could be heard in the background.

One British tourist shared a video on X, with accompanying text reading in part: "3.50am. Sirens going off.

"As a British tourist this scared the hell out of me."

The sirens later stopped and no further alerts were reported.

A spokesperson for the governor of Lublin province, Marcin Bubicz, told WP Wiadomości that authorities had received "credible and confirmed" information from Poland’s Government Security Center about a threat of airstrikes.

Air raid alerts sounded across Ukraine just hours earlier.

Reuters news agency reported that explosions were heard in Kyiv.

Poland, a member of NATO, protectively arranged fighter jets to protect its airspace amid Russian air strikes, its armed forces said on X.

"Fighter aircraft and an early warning aircraft have ‌begun ⁠operations, while ground-based air defence systems and radar reconnaissance systems have reached a state of readiness," they said.

They added that these actions are of a preventive nature.