In an update posted on Facebook, the General Staff of the Armed Forces of Ukraine wrote that Belarus was continuing to support Russia’s war in Ukraine by “providing its infrastructure and airspace.”

“There is still a threat of missile and air strikes, as well as the use of ‘Shahed-136’ attack UAVs [unmanned aerial vehicles] from the territory of the Republic of Belarus,” the update read, referring to a type of Iranian drone Russia has been accused of using against Ukraine. “Covert mobilization of the Belarusian Armed Forces continues under the guise of training sessions. According to available information, measures are being taken to train operators of anti-aircraft missile systems and tank crews.”

Newsweek was not able to independently verify the report and reached out to Belarus’ Foreign Ministry for confirmation and comment.

Belarusian President Alexander Lukashenko has remained a top ally of Russian President Vladimir Putin in the face of global outcry over his ongoing aggression in Ukraine. Belarus has aided Russia in its war by allowing it to stage troops within and launch strikes on Ukraine from its territory, but it has yet to become directly involved in the conflict by sending in troops.

Lukashenko has said that he does not plan to have his country join any war unless it concerns an issue of national defense.

“We will fight only when we have to defend our home, our land,” he told reporters last month.

Lukashenko said at the time that Belarus was regularly conducting military exercises to ensure that people were prepared to defend the country. Additionally, in an interview that aired Sunday with the Belarusian ONT TV channel, the head of the country’s Ministry of Emergency Situations said that weapons have been distributed throughout the country so it can “protect the motherland.”

“The leadership of our country is taking all measures to prevent [a military conflict in Belarus] from happening,” Vadym Sinyavskyi said. “But we understand that, unfortunately, the world is such that there may be a situation in which we will have to act quickly. In particular, within the limits of civil defense.”

The General Staff of the Armed Forces of Ukraine did not say in its update Tuesday if it believed Belarus’ “covert mobilization” was preparation for entering Ukraine or some other purpose, such as national defense.

Still, fears that Belarus could join the war have grown in recent days after Lukashenko vowed earlier this month to conduct joint deployments with Russian forces. The Belarusian leader said Friday that he had introduced “counterterrorist measures” in the country “in connection with the escalation along the perimeter of the borders.” Additionally, he accused Ukraine of planning a strike on Belarusian territory without providing evidence.

There have also been suggestions that Putin could pressure or force Lukashenko into sending his troops into the war-torn country.

Ukrainian presidential adviser Mikhail Podolyak warned in July that Russia “wants to drag Belarus into a war against Ukraine in order to fill its personnel shortages.”