Finland is ready to close its last border crossing with Russia if Moscow keeps pushing migrants across, Prime Minister Petteri Orpo said Monday as migrants continued to make the treacherous journey through the Arctic.

“We have closed all our border stations on the eastern border except for one and we are ready to close the last one if needed,” Orpo told reporters in Helsinki.

“Finland is protecting the European Union’s external border and NATO’s border. We will not let this phenomenon continue,” he added.

Finland has seen a surge in asylum-seekers entering without visas across its 1,300-kilometer border with Russia, with around 800 crossing since August.

The migrants are predominantly from the Middle East and Africa.

This has prompted Finland to close all but its northernmost border crossing, in the remote Murmansk region in the Arctic, over the past two weeks.

Finnish officials claim Russia is attempting to destabilize its Nordic neighbor, with Orpo last week calling it “a systematic and organized action by the Russian authorities.”

In April, Moscow warned it would take “countermeasures … in tactical and strategic terms” after branding Finland’s decision to join NATO as an “assault on our security.”

Since last Thursday, the only border crossing that has remained open is the Raja-Jooseppi station.

Migrants continued to cross there this weekend, with a total of 60 arriving on Saturday, Sunday and Monday, according to the Finnish Border Guard.

Finland is obligated by international law to ensure that migrants can seek asylum, and the availability of locations can be limited only in exceptional circumstances, according to Finnish legal experts.