Unmanned aerial vehicles (UAVs) have been spotted in both Bulgaria and Germany, causing concern that Russia's ongoing conflict in Ukraine may be expanding to NATO nations. In Bulgaria, an explosion occurred near the Trans-Balkan gas pipeline, which links Turkey to Ukraine, with Prime Minister Rumen Radev confirming it was a drone carrying a significant amount of explosives. The incident happened close to the Romanian border and the compressor station of the pipeline. No casualties were reported, but Bulgaria's Defence Ministry suggests the drone was likely a Maya decoy drone, commonly used by Ukrainian armed forces. Ukraine denies intentionally directing any assets towards Bulgaria, and the foreign minister has summoned the Ukrainian ambassador over the incident. In Germany, two drones were spotted at a military base in Mechernich, 35km from the Belgian border. The site houses a high-security underground storage facility for military equipment and is also a base for personnel responsible for maintaining US Patriot air defenses. A similar incident occurred at Leipzig/Halle Airport near several Ukrainian cargo transporters. These drone sightings across Europe have revived concerns about the potential escalation of Russia's war in Ukraine, with some politicians accusing Russia of being involved. However, German government officials have not publicly blamed any foreign countries for this week's drone incursions. The incidents have also sparked debate about whether strategically important NATO members such as Germany are prepared to handle new security threats.