The United States condemned Russia's intention to obstruct navigation in the Black Sea, and called on it to stop its military build-up on the borders of Ukraine, while Kiev called for the imposition of economic sanctions on Moscow.

In a statement issued late Monday evening, US State Department spokesman Ned Price described reports of Russia's intention to ban navigation in parts of the Black Sea as an unjustified escalation, especially since such a measure affects the entry of ships into Ukrainian ports.

Price said that the escalation comes within the framework of Russia's ongoing campaign to undermine and destabilize Ukraine, calling on Moscow to stop harassing ships sailing in the Black Sea.

The US spokesman also urged Russia to reduce the forces it had recently mobilized on the borders of Ukraine and in the Crimean peninsula, which it annexed in 2014.

The Pentagon said earlier on Monday that the current Russian military build-up on the Ukraine border is the largest since 2014.

The Pentagon called on Russia to clarify its intentions regarding Ukraine, to stop provoking it, and to contribute to supporting stability in the region.

The official foreign policy of the Union Josep Borrell confirmed yesterday that Russia has massed 150 thousand soldiers on its borders with Ukraine, noting that it is the largest military deployment there.

Borrell called on Russia to withdraw its forces from the borders with Ukraine, saying that "relations with Russia are not improving, on the contrary, tension is escalating in various fields."

And recently, Russia sent 15 warships to conduct military exercises in the Black Sea, and Washington warned against sending ships there, due to the escalation of tension in the Donbas region in eastern Ukraine, parts of which have been controlled by pro-Moscow separatists since the outbreak of the conflict in 2014.

Russia has deployed its forces on the borders of Ukraine as part of "military exercises" to confront the "threats" of the North Atlantic Treaty Organization (NATO), which Kiev aspires to join.

Sanctions on Russia

Meanwhile, Ukrainian Foreign Minister Dmitry Koliba stressed the importance of imposing economic sanctions targeting various sectors in Russia.

In a statement to Al Jazeera, Kuliba indicated that this measure makes Moscow think twice before attacking his country, as he put it.

He also said that imposing collective sanctions on Russia is the way to prevent it from escalating.

Simultaneously, Kiev announced the expulsion of a Russian diplomat in response to Moscow's expulsion of the Ukrainian consul.

And recently, Ukraine called on the North Atlantic Treaty Organization (NATO) to accelerate its accession procedures, a move which Russia strongly opposes.

Ukrainian maneuvers

On the other hand, the Ukrainian Navy announced on Monday the end of its joint naval military exercises with Romania in the Black Sea, which lasted for a week.

The maneuvers simulated face-to-face combat operations with warships, securing control over shipping areas at sea.

And the Ukrainian Defense Ministry said that its navy will participate in other similar exercises next summer, which will be held in the northwestern part of the Black Sea.

In the meantime, the Ukrainian army continues on the Donbas front ground maneuvers with armored weapons using live ammunition, with the aim of testing the readiness of the forces to repel any attack on that front from the Russian side, improving the soldiers' performance, and giving them combat experience.

The Ukrainian army also announced the killing of one soldier and wounding another in a shooting carried out by the pro-Russian separatists on defensive positions in the Donbas region.

Five violations of the ceasefire were recorded in the vicinity of several towns in Donbas, in which the separatists used anti-tank artillery shells and heavy and light machine guns, according to the Ukrainian army statement.