Lithuania's president and prime minister were forced to take shelter on Tuesday, when a drone alert caused the capital Vilnius to come to a standstill. President Gitanas Nauseda and Prime Minister Inga Ruginiene were taken to emergency shelters following the air alert, which ordered the city's population to take cover. Flights were suspended and road and rail travel briefly ground to a halt. The alert has since been lifted. It is not yet clear who was behind the incursion. It came a day after Estonia said Nato shot down a drone over its territory, which it suspected was a Ukrainian projectile knocked off course by Russian electronic interference. The alert resulted from a drone sighted in neighbouring Belarus, prompting warnings from Lithuania's defense ministry urging citizens to take immediate shelter in a safe place. This incident is the latest of several recent drone incursions affecting NATO members Estonia, Latvia, and Lithuania, demonstrating a critical security concern in the region.