A US Air Force reconnaissance plane flying in international airspace has been shadowed through the skies by a Russian fighter pilot off the country’s Pacific coast, Ministry of Defense officials in Moscow confirmed on Friday.

A spokesperson for the department revealed that the Russian MiG-31 jet “took off from an airfield in Kamchatka to identify [the American plane] and accompany it. The fighter pilot identified the target as a strategic reconnaissance aircraft RC-135.”

The ministry confirmed that the spy plane, equipped with high-tech reconnaissance equipment, had not violated the border and was escorted along its flight path. After the US pilot set a course away from the Russian mainland, the fighter disengaged, reports say.

The incident comes amid a series of diplomatic spats between the two countries. On Thursday, American President Joe Biden signed a decree introducing new sanctions against Russia, banning US companies from directly purchasing shares in Moscow’s foreign debt and expelling ten of its diplomats from Washington. The Kremlin is understood now to be preparing its own measures in response.