Belarus has claimed that a Ukrainian military helicopter intruded one kilometre into its airspace over the weekend.
The Belarusian Foreign Ministry said it had summoned a Ukrainian military attaché to lodge a formal protest over the matter.
Kyiv immediately rejected the allegation and has denied the reported airspace violation.
The Ukrainian border service said the helicopter and drone flights in the area on Saturday were part of efforts to strengthen protections for the 1,084-kilometre border with Belarus.
The dispute comes amid rising tensions between the two neighbouring former Soviet countries, as Ukraine recently launched drills involving 8,000 troops.
Belarus has argued that the Ukrainian military exercises, along with “accusatory rhetoric” by Kyiv, have raised a potential security threat.
The European Union has accused Belarus of waging a "hybrid war" by encouraging migrants to illegally enter the bloc to destabilise the West. Belarusian authorities have denied the accusations and in turn, accused the EU of failing to offer safe passage to migrants.
Meanwhile, tensions are also high between Ukraine and Russia -- an ally of Belarus -- over alleged military activity.
Russia denied having any plans to attack Ukraine but Russian President Vladimir Putin has demanded guarantees from the West blocking NATO’s expansion to Ukraine.
Putin is due to hold a video call with US President Joe Biden on Tuesday to discuss wider tensions in the region.