The US military said a Russian fighter plane clipped the propeller of one of its spy drones and made it crash into the Black Sea in the first such direct encounter between the two powers since Russia invaded Ukraine over a year ago.

The Russia’s defence ministry offered a different account of Tuesday’s incident and its ambassador to the United States said his country viewed the incident involving a US MQ-9 drone and a Russian Su-27 fighter jet as a “provocation”.

The United States conducts regular surveillance flights in the region and has supported Ukraine with tens of billions of dollars in military aid, although it has not become directly engaged in the war.

Russia had shelled dozens of settlements along the eastern front in the past 24 hours including a rocket attack on a civil infrastructure in the Kherson region which caused civilian casualties, the Ukrainian military said on Wednesday.

The battlefield reports could not be verified and Russia denies targeting civilians.

Ukrainian President Voldoymyr Zelenskiy said on Tuesday night that military commanders were unanimously in favour of defending the eastern front line, including the ruined city of Bakhmut, which has been under siege by Russia for months.

“The main focus was on ... Bakhmut,” Zelenskiy said in his nightly video address. “There was a clear position of the entire command: Strengthen this sector and destroy the occupiers to the maximum.”

Zelenskiy dismissed the governors of three regions: Luhansk in the east, Odesa on the Black Sea in the south and Khmelnytskyi in the west. No reason was given in the announcement by the government’s parliamentary representative.

Ukrainian Deputy Defence Minister Hanna Malyar said Russia was “on the offensive” across the entire front in the eastern Donetsk region, with battles also raging around Kreminna and other towns north of Bakhmut.

The defence of Bakhmut was important because a “large amount of enemy material is being destroyed ... A huge number of troops are being killed and as of today, the enemy’s capacity to advance is being reduced”, she told Ukrainian television.

With casualties mounting, Russian lawmakers proposed amendments to the citizenship law to allow for the stripping of acquired citizenship for treason and discrediting what the Kremlin calls its “special military operation” in Ukraine.

On the economic front, talks continued to extend a deal to allow grain shipments from Ukraine’s Black Sea ports that is due to expire this week, the United Nations and Turkey said. Ukraine rejected a Russian push for a 60-day renewal, half the term of the previous renewal.

Drone crash

Two Russian Su-27 jets carried out what the US military described as a reckless intercept of the American spy drone while in international air space. It said the Russian fighter jets dumped fuel on the MQ-9 - possibly trying to blind or damage it - and flew in front of it in unsafe manoeuvres.

After about 30 to 40 minutes, at 7:03 a.m. (0603 GMT), one of the jets then collided with the drone, causing it to crash, the US military said.

Russia has not recovered the drone and the jet was likely damaged, the Pentagon said.

“In fact, this unsafe and unprofessional act by the Russians nearly caused both aircraft to crash,” US Air Force General James Hecker, who oversees the US Air Force in the region, said in a statement.

Russia’s defence ministry denied that its aircraft had come into contact with the unmanned aerial vehicle (UAV), which it said had crashed after “sharp manoeuvring”. It said the drone had been detected near the Crimea peninsula, which Moscow annexed from Ukraine in 2014.

The US State Department summoned Russian Ambassador Anatoly Antonov to discuss what happened, spokesperson Ned Price said.

In remarks published on the embassy website early on Wednesday, Antonov said the American aircraft “deliberately and provocatively” moved towards Russian territory with its transponders turned off.

“The unacceptable activity of the US military in the close proximity to our borders is a cause for concern,” Antonov said. “They are collecting intelligence, which is subsequently used by the Kyiv regime to strike at our armed forces and territory.”

The accounts of the incident over the Black Sea, which is bordered by Russia and Ukraine among other countries, could not be independently verified.

Elisabeth Braw, a senior fellow at the American Enterprise Institute in Washington, said it was a “very sensitive stage in this conflict because it really is the first direct contact that the public knows about between the West and Russia.”

Russian President Vladimir Putin says he invaded Ukraine to defend Russia from a hostile West bent on expanding into historically Russian territories.

Ukraine and its Western allies say Russia is waging an unprovoked war of conquest that has destroyed Ukrainian cities, killed thousands of people and forced millions more to flee their homes.