An alarm sounded on Saturday afternoon by authorities in eastern Poland, in the region bordering Ukraine, reportedly following a drone threat, possibly Russian.

Meanwhile, the Armed Forces in Romania were mobilized and reportedly shot down two Russian drones that entered Romanian airspace from Ukraine.

Romanian authorities sent an emergency alert to residents urging them to stay in a safe place.

Polish and allied fighter jets took off to deal with the threat.

At the same time, Lublin airport and a zone around it were closed while alarm sirens were heard in some areas.

The Polish Armed Forces said the aircraft were involved in an operation near the border with Ukraine “to ensure the safety of our airspace.”

“These actions are of a preventive nature and are aimed at securing airspace and protecting civilians, especially in areas adjacent to the threatened area,” the Polish military command said in the statement.

The statement did not mention any violations of Polish airspace, Reuters notes.

In any case, the mobilization comes just three days after Poland shot down Russian drones when they crossed into its airspace.

The breach by Russian drones took place at night from Tuesday to Wednesday. Russia said it had not targeted Poland.