In what may be a move that could further strain relations between Ukraine and Russia, Ukraine on Saturday closed its ports to Russian ships, several Russian media said.

The new Ukrainian law effectively denied Russian ships (cargo and passengers) access to its internal waters. The proposal to restrict Russian ships in internal waters was proposed by Ukraine in 2018. The country passed a law to this effect in 2020. The law entered into force on January 1, 2022.

This development came on the same day as the Ukrainian army’s report that a Ukrainian soldier was killed during a fight with pro-Russian separatists in the eastern region of the country. It is alleged that the separatists enjoy Russian support, but Russia has repeatedly denied this.

Ukraine and Russia are already at odds over the buildup of Russian troops along the border. Although Russia has said it has no plans to invade Ukraine, it has alleged that Ukraine’s maneuvers create threats to Russia’s security. Ukraine was part of the former Soviet Russia. Russia has already annexed Crimea, which was once part of Ukraine.

Western countries have issued a number of warnings to Russian President Vladimir Putin against invading Ukraine. Putin has made it clear that including Ukraine in the North Atlantic Treaty Organization (NATO) would be unacceptable to Russia.