Aug. 25 (UPI) — For the third time in a month a suspicious drone was discovered at the Leipzig-Halle Airport in Germany along with a suspected military explosive.

German authorities are investigating whether these drone discoveries are tied to a coordinated threat following the first incident on Aug. 5. The thirdincident took place on Aug. 14, when a drone and about 50 grams of explosives was found west of the airport.

German Chancellor Friedrich Merz said the government and German security authorities are “working intensively” on finding those responsible. No suspects have been named.

“They will pay for this,” Merz said.

German media outlets have suspected the drones and explosives are tied to Russian intelligence. The first drone was found near a Ukrainian cargo plane that was to be used to transport military supplies.

German authorities have not yet taken that position publicly. Earlier this month, Interior Minister Alexander Dobrindt said “many indications” pointed to a state actor being behind the threat but did not name a nation or military entity suspected of being involved.

A German intelligence report last year noted that national security had “worsened significantly” since Russia launched its invasion of Ukraine in 2022.

“The drone attack in Leipzig, among other things, shows that we are also facing very real threats,” Merz said ahead of a cabinet retreat in Neuhardenberg, Germany, on Tuesday. “Germany has come under increased scrutiny from hybrid attackers.”