Russian President Vladimir Putin said on Wednesday that Russia and Belarus will conduct joint military exercises early next year.

Putin praised Belarusian President Alexander Lukashenko’s suggestion to organize further military training, which he said may take place in February or March. He said that military officials will coordinate specifics during a meeting with Lukashenko in St. Petersburg.

Putin’s declaration came in the midst of a Russian force buildup near Ukraine, which has heightened Western concerns of an invasion. Some Ukrainian authorities have expressed worry that Russia may launch an attack on the nation from Belarusian territory.

Russia has denied having intentions to attack its neighbor, but has pushed the US and its partners to offer guarantees that NATO will not expand or deploy its armaments in Ukraine – requests that the West has rejected.

Russia and Belarus have a union pact that envisions strong political, economic, and military relations, and Moscow has always supported Lukashenko in the face of Western criticism. This pressure increased following a deadly crackdown on internal demonstrations sparked by Lukashenko’s reelection to a sixth term in an August 2020 election that the opposition and the West claim was rigged.

Since the summer, tensions have risen further due to the presence of thousands of migrants and refugees on Belarus’ border with EU member Poland. The EU has accused Lukashenko of retaliating for sanctions by using needy asylum seekers as pawns and duping them into attempting to enter Poland.

In support of Lukashenko, Russia held large war drills with Belarus in September, involving 200,000 troops. Moscow has put nuclear-capable aircraft on patrol over Belarus many times in recent weeks.

On Wednesday, Russian and Belarusian fighter planes patrolled Belarus’ airspace together.

Lukashenko stated last month that Belarus would be willing to host Russian nuclear weapons.

The Belarusian president has not commented on what types of Russian nuclear weapons Belarus would be ready to accept, but he has underlined that the ex-Soviet country has meticulously kept the required military infrastructure dating back to the USSR’s era.

According to Russian Foreign Minister Sergey Lavrov, Lukashenko’s offer is a “severe warning caused by irresponsible Western behavior.”