A Russian fighter jet on Tuesday struck the propeller of a U.S. surveillance drone over the Black Sea, causing American forces to bring down the unmanned aerial vehicle in international waters, the U.S. military said, an incident that highlighted soaring U.S.-Russian tensions over Moscow’s war in Ukraine.

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

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.

There was no immediate reaction from Moscow, which has repeatedly voiced concern about U.S. intelligence flights close to the Crimean Peninsula, which Russia illegally annexed from Ukraine in 2014.

Amid the continuing fighting in Ukraine, A Russian missile struck an apartment building in the center of Kramatorsk on Tuesday, killing at least one person and wounding nine others in one of Ukraine’s major city strongholds in its eastern Donetsk region.

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.

The Ukrainian general prosecutor’s office and regional Gov. Pavlo Kyrylenko also reported on the attack, posting photos of the building with mounds of rubble in front of it. The impact damaged nine apartment blocks, a kindergarten, a local bank branch and two cars, Kyrylenko said.

The war, which erupted after Russia’s launched its full-scale invasion in February 2022, has brought heavy civilian casualties. Tuesday’s victims were among at least seven civilians killed and 30 wounded in 24 hours, Ukraine authorities said.

They included a 55-year-old woman killed when a Russian shell hit her car Tuesday in a border town in northeastern Ukraine.

“Russian troops are striking residential buildings, schools and hospitals, leaving cities on fire and in ruins,” Kyrylenko, the regional governor, said on Ukrainian television. “The Russians mark each meter (yard) of their advance in the region not only with their own blood, but also with the (lost) lives of civilians.”

Kramatorsk houses the local Ukrainian army headquarters. Ukrainian authorities say it has been regularly targeted by Russian shelling and other attacks in the past.

A missile strike on the city’s train station last April, which Kyiv and much of the international community blamed on Moscow, killed dozens of people and wounded more than 100.

Russian President Vladimir Putin, speaking Tuesday during a meeting with workers at a helicopter factory in southern Siberia, once again cast the conflict in Ukraine as an existential one for Russia, charging that unlike the West — which, he said, is seeking to advance its geopolitical clout — it’s fighting for its existence as a state.

“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.”

Ukrainian forces have also dug in, especially in the devastated eastern city of Bakhmut where Kyiv’s troops have been fending off Russian attacks for seven months and which has become a symbol of Ukraine’s resistance, as well as a focal point of the war.

Zelenskyy discussed the situation in Bakhmut with the top 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 frontline,” Valerii Zaluzhnyi, the commander-in-chief of the Armed Forces of Ukraine, said.

Putin emphasized that his country’s industries have survived the blow of Western sanctions. But he acknowledged those sanctions could bring longer-term problems for the Russian economy.

Russia had welcomed a Chinese peace proposal to end the fighting, but Kremlin spokesman Dmitry Peskov said Tuesday that Kyiv’s refusal to have talks leaves Moscow with only military options.

Beijing has said it has a “no limits friendship” with Russia and has refused to criticize Moscow’s invasion, or even refer to it as an invasion.

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

However, Moscow’s pursuit of its goals in Ukraine has been slowed by poor war management and short resources after being beaten back at the end of last year in a Ukrainian counteroffensive, military analysts say.

The U.K. Ministry of Defense said Tuesday that Russia’s artillery ammunition shortages “have likely worsened to the extent that extremely punitive shell-rationing is in force on many parts of the front.”

That shortcoming, it said, has “almost certainly been a key reason why no Russian formation has recently been able to generate operationally significant offensive action.”

In other developments:

— The Russian parliament’s lower house on Tuesday gave final endorsement to a bill that extends punishment for showing disrespect toward participants in the “special military operation,” which is how the Kremlin officially describes its war in Ukraine. The change makes it punishable to spread allegedly fake information not only about the military, but also members of volunteer units, in an apparent reference to the Wagner Group military contractor. Those convicted of spreading such information face a prison term of up to 15 years. The bill is set to be approved by the upper house before President Vladimir Putin signs it into law.

— Iceland’s prime minister, Katrin Jakobsdottir, made an unannounced visit to Kyiv on Tuesday. She laid flowers at a ceremony for Ukrainian volunteers who have been killed in fighting since 2014, when Russia annexed Ukraine’s Crimean Peninsula and Russia-backed separatists started an insurgency in the eastern Donbas region. Jakobsdottir was expected to meet with President Zelenskyy during her visit.