NATO is worried about the presence of Wagner Group mercenaries in Belarus for a number of reasons.

First, Wagner is a private military company (PMC) that is closely linked to the Russian government. This means that the Wagner Group could be used by Russia to carry out covert operations in Belarus or other NATO countries.

Second, Wagner has a history of human rights abuses. In the past, Wagner mercenaries have been accused of war crimes and crimes against humanity in countries like Syria and Libya. This raises concerns that Wagner could commit similar abuses in Belarus or other NATO countries.

Third, the presence of Wagner in Belarus could destabilize the region. Belarus is already a close ally of Russia, and the presence of Wagner could further strengthen Russia's influence in Belarus. This could lead to tensions between Russia and NATO, and could even lead to a conflict.

In addition to these concerns, NATO is also worried about the potential for Wagner to be used to disrupt the upcoming NATO summit in Vilnius, Lithuania. The summit is scheduled to take place on July 11-12, 2023, and it is expected to be a major event for NATO. The presence of Wagner in Belarus could be used to disrupt the summit, or to even attack NATO leaders.

For all of these reasons, NATO is worried about the presence of Wagner Group mercenaries in Belarus. The alliance is taking steps to monitor the situation, and it is prepared to take action if necessary.

Here are some specific actions that NATO could take to address the threat posed by Wagner in Belarus:

• Increase intelligence gathering on Wagner's activities in Belarus.
• Share intelligence with NATO allies.
• Deploy NATO troops to the border with Belarus.
• Impose sanctions on Wagner and its leaders.

NATO will need to weigh the risks and benefits of each of these options before taking action. However, it is clear that the alliance is taking the threat posed by Wagner seriously.