Washington has summoned Russia’s ambassador to the US to the State Department to express its “strong objection” after a Russian warplane shot down a US surveillance drone over the Black Sea on Tuesday, prompting US forces to bring the drone down in international waters.

“We will summon the Russian ambassador to the State Department,” US diplomatic spokesman Ned Price told a press briefing, calling the incident a “flagrant violation of international law.”

He added that the US ambassador in Moscow had also conveyed Washington’s protests in a message to the Russian Foreign Ministry.

The US military says a Russian Su-27 jet collided with the unmanned aerial vehicle over the Black Sea, forcing the drone down.

The US European Command said in a statement that two Russian Su-27 fighter jets “conducted an unsafe and unprofessional interception” of a US MQ-9 drone operating in international airspace over the Black Sea.

It said one of the Russian fighters “struck the propeller of the MQ-9, forcing US forces to land the MQ-9 in international waters”, adding that several times before the collision the Su-27s dumped fuel and flew in front of MQ-9 in “a reckless, environmentally unsound and unprofessional manner.”

“This incident demonstrates a lack of competence in addition to being unsafe and unprofessional,” it added.

White House national security spokesman John Kirby said US President Joe Biden was briefed on the incident by national security adviser Jake Sullivan.

Russian and American aircraft have operated over the Black Sea throughout the war, but this is the first known such interaction, a potentially dangerous escalation at a critical time in the fighting.

The Reaper drone, manufactured by the American company General Atomics, is a remote-controlled aircraft of the MALE (medium altitude long endurance) type, equipped with ultra-modern onboard sensors (optronic ball and radar) to perform surveillance operations at a cruising speed of 335 km/h.

With a wingspan of 20 meters, it has an endurance of more than 24 hours of flight. It can carry several types of weapons: lasers and/or GPS-guided bombs (GBUs) or Hellfire missiles. Its ground crew consists of four people.

In addition to the US, several European armies have Reaper drones in their navies, including the British, Italian, French and Spanish.

The skies above the Black Sea are the scene of regular interactions between drones and aircraft from NATO countries and the Russian armed forces.