Russia appears to be testing the resolve of Donald Trump's young presidency with a series of belligerent moves while America's NSA is dealing with an internal crisis.

Four Russian military aircraft conducted low passes against a U.S. destroyer in the Black Sea just days before a spy ship was spotted off the East Coast.

The USS Porter, a guided missile destroyer, reported the aircraft performing 'dangerous flybys' past the ship which was based just off the coast of Romania on February 10.

'There were several incidents involving multiple Russian aircraft,' said Navy Capt. Danny Hernandez, spokesman for the European Command. 'They were assessed by the commanding officer as unsafe and unprofessional.

On top of that, Russia has also reportedly deployed a new cruise missile, apparently violating an arms control treaty banning ground-based US and Russian intermediate-range missiles.

Four Russian military aircraft conducted low passes against a U.S. destroyer in the Black Sea just days before a spy ship was spotted off the East Coast (stock image)

The USS Porter was taking part in a military exercise in The Black Sea at the time

'USS Porter queried all aircraft and received no response,' Hernandez said.

'Such incidents are concerning because they can result in accident or miscalculation,' he said referring to actions that could spark an unintended shootout by military forces.

The incidents involving the Su-24 were considered to be unsafe and unprofessional by the commanding officer of the Porter because of their high speed and low altitude, while the IL-38 flew at an unusually low altitude, Hernandez said.

Another U.S. official, speaking on condition of anonymity, said the closest incident that day involved the lone SU-24, which came within 200 yards of the Porter at an altitude of 300 feet (91 meters).

The move was the first such act of Russian military aggression towards U.S. forces since Trump's inauguration. But the country has been quick to follow up after a Russian intelligence-gathering ship was spotted roaming the waters off the East Coast.

The SSV-175 Viktor Leonov ship was 70 miles off the coast of Delaware - in international waters - heading north, officials told Fox News.

Armed with surface-to-air missiles, the ship is capable of intercepting communications and can measure U.S. Navy sonar capability, an official said.

The USS Porter, a guided missile destroyer, reported the aircraft performing 'dangerous flybys' on February 10

Russia has also deployed a new cruise missile despite complaints by U.S. officials that it violates an arms control treaty banning ground-based U.S. and Russian intermediate-range missiles. (file above of Russian President Vladimir Putin)

'It's not a huge concern, but we are keeping our eyes on it,' they added.

The Viktor Leonov, which measures 300 feet long and 47.5 feet wide, has a crew of 200 sailors carries high-tech electronic surveillance equipment and weaponry, AK-630 rapid-fire cannons and surface-to-air missiles.

It is the first such move by Russian military under Trump's presidency.

The ship sighting and missile deployment also comes as Trump demanded his national security adviser's resignation on Monday night after concluding that an 'eroding level of trust' had made it impossible to leave him in the sensitive position.

Russia has also deployed a new cruise missile apparently violating an arms control treaty banning ground-based U.S. and Russian intermediate-range missiles.

The nation has secretly deployed the ground-launched SSC-8 cruise missile that Moscow has been developing and testing for several years, despite U.S. complaints that it violated sections of the 1987 Intermediate-range Nuclear Forces treaty, The New York Times reported.

The missile deployment and ship sighting comes as Trump (far left) demanded the resignation of Michael Flynn (far right), his national security adviser for talking to the Russian ambassador

The intelligence-gathering ship Viktor Leonov has been spotted on and off around the East Coast over the past few years (pictured in Havana in 2014)

The Russian Defense Ministry did not immediately respond to requests for comment on the New York Times story.

During the Black Sea incident, two Russian Su-24 jet fighters had buzzed the ship, followed by a single Su-24 and then an IL-38 transport aircraft.

The aircraft failed to respond to several radio requests from the U.S. military to halt the overflights, and did not have their electronic identifying transponders activated - used to help identify hostile and friendly aircraft on radar.

THE RUSSIAN SPY VESSEL VIKTOR LEONOV The Vishnya class intelligence-gathering ship went into service in the Black Sea in 1988 before it was transferred seven years later to the northern fleet. It named after Second World War Soviet sailor Viktor Leonov. Ship measures 300 feet long and 47.5 feet wide. It has a crew of 200 sailors carries high-tech electronic surveillance equipment and weaponry, AK-630 rapid-fire cannons and surface-to-air missiles. Advertisement

The buzzing of the USS Porter, which had been taking part in an annual international military exercise called Sea Shield, occurred in international waters off the Romanian coast.

Russia's actions prove to be a challenge for President Donald Trump, as he had pledged to improve the relations between the U.S. and Russia by working with President Vladimir Putin during his campaign.

'I respect a lot of people,' Trump told Fox News. 'But that doesn't mean I am going to get along with him. He's a leader of his country. I say it's better to get along with Russia than not. Will I get along with them? I have no idea.'

Prior to Trump's administration, the last encounter between the Russian and U.S. military came when two Russian jets flew dangerously close to U.S. P-8A maritime patrol aircraft over the Black Sea.

Russian bombers also recently completed a major nuclear exercise.

Sea Shield is a joint exercise between the U.S. and NATO to support member states concerned about Russian aggression following its take over of Crimea.