WARSAW, July 2 (Reuters) - Poland said on Sunday it will send 500 police to shore up security at its border with Belarus to cope with rising numbers of migrants crossing as well as any potential threats after the Wagner group of mercenaries relocates to Belarus.

"Due to the tense situation on the border with Belarus I have decided to bolster our forces with 500 Polish police officers from preventive and counter-terrorism units," Minister of Interior Mariusz Kaminski wrote on his Twitter account.

The police force would join 5,000 border guards and 2,000 soldiers in securing the border, he said.

Poland has accused Belarus of artificially creating a migrant crisis on the border since 2021 by flying in people from the Middle East and Africa and attempting to push them across the frontier.

The Polish Border Guard said on Sunday that 187 people tried to cross into Poland from Belarus illegally on Saturday, and numbers have been growing steadily in recent months, although they are well below levels seen in 2021.

A spokeswoman for Poland's Border Guard said that Polish patrols at the border have also faced more aggressive behaviour in the past two months as the number of migrants rose.

"The groups are more aggressive. There have been many attacks on Polish patrols. Seventeen vehicles have been damaged this year, of which 13 in June alone," Border Guard spokeswoman Anna Michalska said.

Deputy Minister Coordinator of Special Services Stanislaw Zaryn told Reuters the bigger security presence was also in response to the transfer of Wagner group mercenaries to Belarus.

Russian President Vladimir Putin's decision to offer troops from the private military company the choice of relocating to Belarus has led to fears among eastern NATO members that their presence will cause greater instability in the region.

"It is still a matter of analysis and hypotheses whether the Wagner group will engage in destabilising Poland and will also be active in coordinating the migration route," Zaryn told Reuters by phone.

"We assume the Wagners aren't going to Belarus to recuperate, but to carry out a mission. This mission could be aimed at Poland, but also against Lithuania or Ukraine," he added.