Ukraine’s border guard announced on Thursday morning that Russian troops had attacked the country along its border with Belarus.

The agency announced that Russian artillery had fired on Ukrainian positions from within Belarus at roughly 5:00 am, leading Ukrainian soldiers along the border to fire back. No information on casualties from the attack was provided.

“The state border of Ukraine in the area with the Russian Federation and the Republic of Belarus was attacked by Russian troops supported by Belarus,” the agency wrote in a statement. The Ukrainian border guard also noted that a second attack had taken place from the Crimean Peninsula, which has been occupied by Russia since 2014.

Later in the morning, CNN reported that troops from the Belarusian city of Beselovka had crossed the Ukrainian border and entered the city of Senkivka, which is positioned near a three-way border crossing between Russia, Ukraine, and Belarus.

The U.S. Embassy in Kyiv, which was relocated out of Kyiv last week, announced on Thursday morning that it was “aware of military engagements” that had taken place along Ukraine’s borders.

Russian troops have been present in Belarus since they were deployed to the country in late January for a series of joint Russo-Belarusian military exercises. Although the Russian and Belarusian governments insisted that the troops would be deployed for the duration of the exercises and would then return to Russia, security officials in the West warned that in light of escalating tensions between Russia and Ukraine, the exercises might have been intended as a ruse to put a significant Russian troop presence in place for an invasion of Ukraine from the north.

Those fears now appear to have come to fruition. Kyiv is less than one hundred miles from the Belarusian border, and the land in between is sparsely populated. The participation of Belarusian troops in the attacks against Ukraine led several commentators to argue that Belarus’s leader, Alexander Lukashenko, should be considered an instigator of the war alongside Russian leader Vladimir Putin.

“Belarus MUST be part of the sanctions package,” wrote former U.S. Ambassador to Russia Michael McFaul on Twitter. “Lukashenko is an ally in Putin’s horrific war.”

“Russia, with the participation of Lukashenka’s regime, launched a groundless and shameless military aggression against Ukraine. The regime turned our country into an aggressor,” Belarusian opposition leader-in-exile Sviatlana Tsikhanouskaya wrote. “But Belarusians don’t want war. Belarus strongly condemns this move and stands with Ukraine.”

Trevor Filseth is a current and foreign affairs writer for the National Interest.

Image: Reuters.