Belarusian President Alexander Lukashenko says his country has conducted a "special operation" and rescued Belarusians detained in Ukraine.

A Belarusian state-run media outlet said on Thursday Lukashenko made the comment during a national security meeting with officials in the capital Minsk.

The news agency quoted Lukashenko as saying "scoundrels" in Ukraine had captured about 1,500 vehicles and some 100 Belarusian drivers.

Lukashenko said Belarus had warned Ukraine it would be forced to carry out a "special operation" to free those detained. He added Belarus had executed the operation and rescued them.

Lukashenko did not provide details on the operation, such as when and where it took place, or whether the military was involved.

The news agency also cited Lukashenko as saying he expects to hold talks with Russian President Vladimir Putin in the next few days.

Belarus, Russia's ally, borders Ukraine to the north. The Kremlin sent troops from both Russia and Belarus when it launched its invasion of Ukraine in late February.

The Belarusian military denies involvement in the invasion. But a senior US Defense Department official said on Wednesday there were indications Russian troops who withdrew from areas around the Ukrainian capital Kyiv are refitting and resupplying in Belarus and Russia.

Analysts say Belarusian troops could join the invasion as Russian forces have purportedly been unable to gain as much ground as the Kremlin had hoped.