Two NATO members said Sunday that Russian drones violated their airspace, as one reportedly flew into Romania during nighttime attacks on neighboring Ukraine while another crashed in eastern Latvia the previous day.

A drone entered Romanian territory early Sunday as Moscow struck “civilian targets and port infrastructure” across the Danube in Ukraine, Romania’s Ministry of National Defense reported. It added that Bucharest had deployed F-16 warplanes to monitor its airspace and issued text alerts to residents of two eastern regions.

It also said investigations were underway of a potential “impact zone” in an uninhabited area along the Romanian-Ukrainian border. There were no immediate reports of casualties or damage.