WARSAW, Poland (AP) — Polish Prime Minister Donald Tusk on Saturday traveled to the country’s border with Belarus, which is also the European Union’s external border with the autocratic state, and pledged to do more to strengthen security along its entire eastern frontier.

Tusk accused Belarus, Russia’s ally, of intensifying what he called a “hybrid war” against the West by encouraging migrants to try to cross into the EU. He vowed that Poland would spare no expense on its border security.

“I know that there are more and more illegal crossings every day,” Tusk told reporters at the border, where he met with Polish Army soldiers, Border Guard officers and police.

The visit to the border, Tusk’s first since he took office in December, comes after a Polish judge defected to Belarus this month. He claimed he was facing persecution in Poland, a democracy, but officials have denounced him as a traitor and he is being investigated on suspicion of espionage.