BERLIN (AP) — Polish authorities said the two people detained on suspicion of flying a drone over state buildings on Monday night were Belarusian and Ukrainian citizens.

The drone, which was spotted flying over the Belvedere presidential palace in the capital, Warsaw, was neutralized by the State Protection Services.

The two suspects are “a young Belarusian woman” and a Ukrainian man “in his early 20s,” Jacek Dobrzynski, a spokesman for the minister coordinating special services, said in a press briefing on Tuesday morning.

Prime Minister Donald Tusk had initially written on social media on Monday night that “two Belarusian citizens” were detained. It was not immediately clear why the initial information was incorrect, but the State Protection Services said that police interrogated the suspects overnight.

“We deny rumors that this is a massive espionage action,” Dobrzynski said, adding that it was too early to confirm any further details.

The country is on high alert after multiple Russian drones crossed into the country last week in what European officials described as a deliberate provocation. NATO sent fighter jets to shoot down the drones.