Poland's prime minister says more than 100 fighters with the private military firm Wagner Group in Belarus have moved close to the Polish border. Belarus shares a border with Poland.

Mateusz Morawiecki said on Saturday that the Wagner members are heading toward the Suwalki Gap, which is a stretch of the Polish-Lithuanian border separating Belarus and the Russian exclave of Kaliningrad.

The area is strategically important for Poland and Lithuania, both NATO members.

Morawiecki said, "Now the situation is becoming even more dangerous."

He warned that Wagner mercenaries may pose as migrants to enter Poland. He described their move as a "step towards a further hybrid attack on Polish territory."

Russian ally Belarus is believed to have been harboring Wagner members since they staged a short-lived armed rebellion against Moscow last month.

Belarusian President Alexander Lukashenko said earlier this month that Wagner fighters wanted to go to Poland in the West, apparently to keep NATO in check.

Poland moved 1,000 troops to the eastern part of the country amid concerns over the presence of Wagner forces near its border.