US President Joe Biden called on his citizens in Ukraine to leave, warning of a world war that could break out at any moment, "if the Russians and Americans start shooting at each other."

These statements came in the wake of a diplomatic stalemate and an exchange of accusations between the two camps of fabricating the crisis.

Biden said things could quickly deteriorate in Ukraine if war broke out, and that American citizens should leave for now.

In an interview with NBC, he added that he would not send troops to Ukraine to evacuate American citizens if there was a Russian invasion.

Biden denied the existence of any scenario to take such a step, saying that when the Americans and Russians start shooting at each other, it will be a world war.

The US State Department had warned US citizens not to travel to Ukraine according to the fourth level, which is the highest, due to the growing fears of military action by Russia.

A State Department statement also called on those in Ukraine to leave immediately through commercial or private means.

At the same time, the ministry recommended those who prefer to stay in Ukraine to be very careful due to possible hostilities in the event of Russian military action.

For his part, John Kirby, a spokesman for the US Department of Defense (Pentagon), said that Russia poses a threat to Ukraine, and it continues to threaten it by deploying its forces on the border.

In an interview with Al Jazeera, Kirby added that any Russian invasion of Ukraine would have severe economic repercussions.


Diplomatic failure

Meanwhile, Russia and Ukraine said they had failed to achieve any breakthrough after a day of talks in Berlin between the parties to the so-called "Normandy formula" to resolve the Ukrainian crisis, which includes Russia and Ukraine along with France and Germany.

After the talks, Russian envoy Dmitry Kozak said it was not possible to reconcile Russia and Ukraine's differing interpretations of the 2015 agreement aimed at ending fighting between pro-Russian separatists and Ukrainian government forces.

On the other hand, Ukraine's envoy Andrei Yermak said that there was no breakthrough, but the two sides agreed to continue talks.

The Berlin meeting is the second after a similar meeting that was held in Paris two weeks ago.

For his part, Russian President Vladimir Putin confirmed the continuation of talks on the Ukrainian crisis between his country and its European and American partners in public and behind closed doors.

Putin said he expected to receive a phone call from his French counterpart, Emmanuel Macron, after the latter finished his consultations with Western countries.


An adventure with dire consequences

In the midst of the continuation of the diplomatic movement, the Director of the Russian Foreign Intelligence Service, Sergey Naryshkin, accused Western countries of pushing Ukraine towards a military adventure with dire consequences, while the North Atlantic Treaty Organization (NATO) declared preparedness for the worst possible scenario.

For his part, Ukrainian Foreign Minister Dmytro Kuleba said that Russia is the only party that causes a military escalation.

NATO Secretary-General Jens Stoltenberg also said that the alliance's defense ministers will discuss next week the reinforcement of forces in southern and eastern Europe.

For his part, British Prime Minister Boris Johnson described the situation as worrying, in light of the heavy deployment of Russian forces in the vicinity of Ukraine, but said that a decision on war had not yet been taken, despite these measures.

Earlier yesterday, British Foreign Secretary Liz Truss held talks with her Russian counterpart Sergey Lavrov in Moscow.

The British Foreign Secretary said that Russia has two options, respecting the sovereignty of Ukraine or the escalation and its repercussions, while the Russian Foreign Minister described the talks with her as a deafening dialogue.

Lavrov stressed that his country does not want to threaten anyone, but rather receives threats, noting that he does not rule out the evacuation of key employees from the Russian embassy in Kiev, after similar measures for other countries.

He expressed his belief that the West is using the escalation in the Ukrainian file to restore the collapsed popularity of Western politicians, as he described it.


Maneuvers and reinforcements

On the ground, the Russian Ministry of Defense announced the launch of exercises for rapid deterrence forces from Russia and Belarus under the name "Union Will 2022" on Belarusian soil.

For its part, the Belarusian Ministry of Defense confirmed that the 10-day exercises are defensive in nature and do not pose a threat to the European community or neighboring countries.

In the opposite camp, Ukrainian Defense Minister Oleksiy Rzhenkov announced the start of military exercises throughout the country.

Rzhenkov added that these maneuvers will be held in areas corresponding to the maneuvers that Russia is conducting on its borders, especially those that started yesterday, Thursday, on the territory of Belarus.

In a related context, BuzzFeed news website reporter published a number of satellite images taken during the past 24 hours, which he said show the continuous Russian military reinforcements in Crimea and Belarus.

The reporter added in a tweet that these photos reveal the new and wide spread operations throughout the region.

Meanwhile, the Russian Defense Ministry said that 65 foreign planes conducted reconnaissance operations near Russian airspace over the past week.

US B-52 bomber (Reuters)

launchers access

On the other hand, the US Air Force announced the arrival of four B-52 Stratofortress bombers to the RAF base to participate in joint air exercises.

And it said in a statement that the four planes took off from Minot Air Base in North Dakota, and arrived at the British "Ruff Fairford" base to train for the joint US-European force missions.

Eric Anthony, a spokesman for the US Air Force in Europe and Africa, ruled out that the arrival of the planes was in response to the current tension between Ukraine and Russia.