A Russian Su-35 jet intercepted a Polish border guard aircraft over the Black Sea near Romania, an incident which caused the plane's pilot to lose control of the aircraft on Sunday.

The Polish border force accused the Russian jet of carrying out "aggressive and dangerous maneuvers" as it approached the border control plane with no prior warning and came into alarmingly close proximity to the Polish aircraft. This led the crew to lose control of the plane and to loss of altitude and turbulence, according to the border guard spokesperson Anna Michalska.

Romania claimed that the Polish border guard plane was on a routine Frontex patrol with Romanian border police Friday when it was intercepted.

The official further explained that "the Russian jet flew just in front of the nose of the Polish plane, crossing its trajectory at a dangerous distance, estimated by the crew at about five meters," further claiming that the Su-35 jet approached the Polish plane on 3 separate occasions. 

In a press release, the Romanian Defense Ministry stated that the Russian jet's behavior was completely unacceptable.

"This incident is a further proof of the provocative approach of the Russian Federation in the Black Sea," the Ministry said.

After the incident, two Romanian and two Spanish combat aircraft were alerted by the NATO Combined Air Operations Centre in Torrejjon Spain to ready themselves to intervene, however, such an event proved unnecessary, according to the Romanian Ministry.

The Polish government's spokesperson Piotr Muller said, "It looks like a planned provocation by Russia, the crew acted responsibly and luckily nothing happened. We can see that Russia is trying to draw international attention by such provocations."

The Polish plane was deployed in Romania on April 19 and is expected to remain in the country until May 17, as it carries out patrol operations for the European Union's border agency Frontex over the Black Sea.