Washington: United States Defence Secretary Lloyd Austin told Russia that their aircraft will continue to "fly and operate wherever international law allows," a day after the Russian Su-27 fighter jet downed an American military drone over the Black Sea, reported CNN.

In the meeting of the Ukraine Defence Contact Group, Austin said this "episode is part of a pattern of aggressive, risky, and unsafe actions in international airspace".

"So make no mistake, the United States will continue to fly and to operate wherever international law allows. And it is incumbent upon Russia to operate as military aircraft in a safe and professional manner," he added.

Austin was the first cabinet member in the administration to directly address the incident, which happened on Tuesday when two Russian Su-27 aircraft intercepted a US MQ-9 Reaper drone, CNN reported.

The downing of the drone marked the first time Russian and US military aircraft have come into direct physical contact since Moscow launched its invasion of Ukraine.

On Wednesday, the Russian Defence Ministry said the US drone, MQ-9 unmanned aerial vehicle was detected flying over the Black Sea near the Crimean Peninsula, in violation of the boundaries of the area of the temporary airspace regime established during the special operation.

"On 14 March 2023 in the morning, the Russian airspace control systems detected an American MQ-9 unmanned aerial vehicle flying over the Black Sea near the Crimean Peninsula in the direction of the state border of the Russian Federation," read the Russian Defence Ministry statement.

The Reaper drone and two Russian Su-27 aircraft were flying over international waters over the Black Sea on Tuesday when one of the Russian jets intentionally flew in front of and dumped fuel on the unmanned drone several times, a statement from US European Command said.

Meanwhile, the US State Department summoned Russian Ambassador Anatoly Antonov to convey "our strong objections", department spokesman Ned Price, reported CNN.

Price also stated that US Ambassador to Russia, Lynne Tracy "has conveyed a strong message to the Russian Ministry of Foreign Affairs".

The incident is likely to increase tensions between the two nations, with the US calling Russia's actions "reckless, environmentally unsound and unprofessional".

President Joe Biden was briefed on the incident by National Security Adviser Jake Sullivan on Tuesday morning, according to National Security Council communications coordinator John Kirby, reported CNN.

Defence Department officials "have not spoken specifically to Russian authorities" on the incident, Ryder said.

Price said separately the US has "engaged at high levels with our allies and partners" to brief them on the incident. He added that the US was "not in a position to speak to what the Russians intended to do" with the manoeuvres, but that ultimately the intent mattered less than "what actually transpired."