KYIV, Ukraine — A Russian fighter jet struck the propeller of a U.S. surveillance drone over the Black Sea on Tuesday in a “brazen violation of international law,” causing American forces to bring down the unmanned aerial vehicle, the U.S. said.

Moscow said the U.S. drone maneuvered sharply and crashed into water following an encounter with Russian fighter jets scrambled to intercept it near Crimea, but insisted its warplanes didn’t fire their weapons or hit the drone.

The incident, which added to Russia-U.S. tensions over Moscow’s war in Ukraine, appeared to mark the first time since the height of the Cold War that a U.S. aircraft was brought down after an encounter with a Russian warplane.

U.S. President Joe Biden was briefed on the incident by national security adviser Jake Sullivan, according to White House National Security spokesman John Kirby. He added that U.S. State Department officials would be speaking directly with their Russian counterparts and “expressing our concerns over this unsafe and unprofessional intercept.”

State Department spokesman Ned Price called it a “brazen violation of international law.” He said the U.S. summoned the Russian ambassador to lodge a protest and the U.S. ambassador to Russia, Lynne Tracy, has made similar representations in Moscow.

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

It said one of the Russian fighters “struck the propeller of the MQ-9, causing U.S. forces to have to bring the MQ-9 down in international waters.” Prior to that, the Su-27s dumped fuel on and flew in front of the MQ-9 several times before the collision in “a reckless, environmentally unsound and unprofessional manner,” the U.S. European Command said in a statement from Stuttgart, Germany.

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

U.S. Air Force Gen. James B. Hecker, commander of U.S. Air Forces Europe and Air Forces Africa, said the MQ-9 aircraft was “conducting routine operations in international airspace when it was intercepted and hit by a Russian aircraft, resulting in a crash and complete loss of the MQ-9.” He added that “in fact, this unsafe and unprofessional act by the Russians nearly caused both aircraft to crash.”

Pentagon spokesman Air Force Brig. Gen. Pat Ryder said the incident occurred at 7:03 a.m. Central European time (0603 GMT; 2:03 a.m. EST) over international waters, and well clear of Ukraine, after the Russian jets had flown in the vicinity of the drone for 30 to 40 minutes. There did not appear to be any communications between the aircraft before the collision, Ryder added.

The MQ-9 is capable of carrying munitions but Ryder would not say whether it was armed. The U.S. had not recovered the crashed drone, U.S. Air Forces-Europe said in a statement, and neither had Russia, Ryder said.

He said it appeared the Russian aircraft also was damaged in the collision but the U.S. has confirmed that warplane did land, although Ryder would not say where.

Russia’s Defense Ministry said the U.S. drone was flying over the Black Sea near Crimea and intruded in the area that was declared off limits by Russia as part of what it calls its “special military operation” in Ukraine, causing the military to scramble fighters to intercept it.

“As a result of sharp maneuver, the MQ-9 drone went into uncontrollable flight with a loss of altitude and crashed into water,” it said. “The Russian fighters didn’t use their weapons or impact the unmanned aerial vehicle, and they safely returned to their base.”

Moscow has repeatedly voiced concern about U.S. intelligence flights close to the Crimean Peninsula, which Russia illegally annexed from Ukraine in 2014. The Kremlin has charged that by providing weapons to Ukraine and sharing intelligence information with Kyiv, the U.S. and its allies have effectively become engaged in the conflict.

Kirby emphasized that the incident wouldn’t deter the U.S. from continuing their missions in the area.

“if the message is that they want to deter or dissuade us from flying, and operating in international airspace, over the Black Sea, then that message will fail,” Kirby said. “We’re going to continue to fly and operate in international airspace over international waters. The Black Sea belongs to no one nation.”

The U.S. European Command said the incident followed a pattern of dangerous actions by Russian pilots while interacting with U.S. and Allied aircraft over international airspace, including over the Black Sea.

“These aggressive actions by Russian aircrew are dangerous and could lead to miscalculation and unintended escalation,” it warned.

Gen. David Berger, commandant of the Marine Corps, said this type of collision is his greatest concern, both in that part of Europe as well as in the Pacific.

“Probably my biggest worry both there and in the Pacific is an aggressive Russia or China pilot or vessel captain, or something gets too close, doesn’t realize where they are, and causes a collision,” Berger said, in response to a question at a National Press Club event Tuesday.

Amid continued fighting in Ukraine, a Russian missile struck an apartment building Tuesday in the eastern city of Kramatorsk, killing at least one person and wounding nine others in one of the major urban strongholds the Donetsk region.

The victims were among seven civilians killed and 30 wounded in 24 hours, Ukrainian authorities said.

Ukrainian President Volodymyr Zelenskyy posted a video showing gaping holes in the façade of the low-rise building that bore the brunt of the strike that damaged nine apartment blocks, a kindergarten, a bank branch and two cars, said regional Gov. Pavlo Kyrylenko.

“Russian troops are striking residential buildings, schools and hospitals, leaving cities on fire and in ruins,” Kyrylenko said.

Russian President Vladimir Putin, speaking with workers at a helicopter factory in southern Siberia, again cast the conflict in Ukraine as an existential one for Russia.

“For us, it’s not a geopolitical task,” Putin said, “it’s the task of survival of Russian statehood and the creation of conditions for the future development of our country.”

Russia had welcomed a Chinese peace proposal, but Kremlin spokesman Dmitry Peskov said Kyiv’s refusal to talk leaves Moscow with only military options.

“We must achieve our goals,” Peskov told reporters. “Given the current stance of the Kyiv regime, now it’s only possible by military means.”

The Russian onslaught has focused on the devastated eastern city of Bakhmut, where Kyiv’s troops have been fending off attacks for seven months and which has become a symbol of resistance, as well as a focal point of the war.

Zelenskyy discussed Bakhmut with the military brass and they were unanimous in their determination to face down the Russian onslaught, according to the presidential office.

“The defensive operation in (Bakhmut) is of paramount strategic importance to deterring the enemy. It is key for the stability of the defense of the entire front line,” Valerii Zaluzhnyi, the commander-in-chief of the Armed Forces of Ukraine, said.