Ukrainian President Volodymyr Zelenskyy Thursday announced martial law across the country as Russian troops entered the border and hit targets around Kyiv.

In a video posted on his Telegram channel, Zelenskyy said Russia launched strikes against Ukrainian military facilities and border guard units.

"Explosions were heard in many cities of Ukraine. We are declaring martial law across the country," he said.

Russia has launched a full-scale invasion of Ukraine and is targeting key areas in cities with weapons and missiles, according to reports.

On early Thursday, explosions were reported in several Ukrainian provinces, including the capital Kyiv, and several tanks reportedly crossed the border with Belarus into Ukraine.

In a statement on Thursday morning, the Russian Defense Ministry announced it is using “high-precision weapons” to disable air defense systems, military airports, and air forces in Ukraine.