Russia expelled a British diplomat who worked at the embassy in Moscow Tuesday, accusing him of spying, marking the latest blow to the two countries’ worsening diplomatic relations.

Russia’s Federal Security Service (FSB) alleged that the British diplomat intentionally provided false information to enter the country as a cover for espionage work, “thereby violating Russian law,” according to state media TASS.

“The Russian FSB has identified signs of intelligence and subversive work by the said diplomat that threatens the security of the Russian Federation,” TASS cited the security service as saying.

The Russian Foreign Ministry subsequently revoked the diplomat’s diplomatic accreditation and ordered him to leave Russia within two weeks, TASS reported.

Russia’s FSB claimed the diplomat was sent to Moscow to “replace” one of six alleged British intelligence officers that Russia expelled this summer.

In August, Russia revoked the accreditation of the diplomats, also on allegations of espionage. At the time, Britain described the accusations as “completely baseless.”

Relations between the UK and Russia have been increasingly strained as Russia continues its full-scale invasion of Ukraine.

The UK has joined the heavy sanctions imposed by Western nations against Russia and pledged billions of dollars of military and economic support to Ukraine since 2022.

Last week, Ukraine launched the British-French-made Storm Shadow missiles at targets inside Russia for the first time, according to a Russian military blog and Reuters, a day after Ukraine fired US-made ATACMS missiles into Russia.

That prompted direct condemnation from Russian President Vladimir Putin, who said the Kremlin’s launch of a new medium-range ballistic missile last week was a response to the “reckless decisions” of Western countries in supplying weapons to Kyiv.

Meanwhile, Russia launched a “record” 188 drone attacks on Ukraine overnight, according to the Ukrainian Air Force on Tuesday.

Russia fired four more Iskander-M ballistic missiles at Ukraine, the Air Force said. The attack damaged critical infrastructure in the western Ukrainian city of Ternopil, causing power outages, according to the local military administration.

In the Kyiv region, air defense interceptions could be heard operating throughout the night. Several residential homes were damaged by the downed drones, which shattered windows of houses, Kyiv authorities said.

Clare Sebastian and Maria Kostenko contributed to this report.