The buildings of the British Embassy are seen in Moscow, Russia, March 15, 2018.
The buildings of the British Embassy are seen in Moscow, Russia, March 15, 2018.

Russian Foreign Minister Sergey Lavrov says Moscow will expel British diplomats "soon" in retaliation for British Prime Minister Theresa May's plan to expel 23 Russian diplomats over the poisoning of a former Russian double spy.

In remarks Thursday in Moscow, Lavrov called May's actions "boorish" and said it was intended to distract from Britain's difficult negotiations in leaving the European Union.

Russian Foreign Minister Sergey Lavrov gestures du
FILE - Russian Foreign Minister Sergey Lavrov gestures during a meeting with South Korean head of National Security Chung Eui-yong at the Russian foreign ministry in Moscow, March 13, 2018.

Lavrov said Moscow will inform London directly through official channels before going public with its response.

Former spy Sergei Skripal and his daughter, Yulia, were found unconscious on a park bench in the English town of Salisbury and rushed to the hospital, where they remain in serious condition. Several other individuals, including a police officer, were sickened.

The forensic tent, covering the bench where Sergei
The forensic tent, covering the bench where Sergei Skripal and his daughter Yulia were found, is repositioned by officials in protective suits in the center of Salisbury, Britain, March 8, 2018.

Britain has said it believes Russia was behind the attack and Prime Minister May announced a series of reprisals, including the largest expulsion of Russian diplomats since 1971, at the height of the Cold War. Russia has denied involvement.

The White House issued a statement Wednesday that said the U.S. "stands in solidarity with its closest ally, the United Kingdom" and shares in the assessment "that Russia is responsible for the reckless nerve agent attack on a British citizen and his daughter, and we support Britain's decision to expel Russian diplomats as a just response.

British officials said the chemical nerve agent known as Novichok was used in the attack. It was developed by the Soviet Union and inherited by Russia.

FILE - Sergei Skripal, a former colonel of Russia'
FILE - Sergei Skripal, a former colonel of Russia's GRU military intelligence service, looks on inside the defendants' cage as he attends a hearing at the Moscow military district court, Russia, Aug. 9, 2006.

Skripal, a former agent of Russia's military intelligence agency, was arrested in 2004 for betraying dozens of Russian agents to Britain. He was freed in 2010 as part of an exchange of spies with the United States, and eventually settled in Britain.

French President Emmanuel Macron said Thursday that his government will take "measures" in the coming days in response to the poisoning of Skripal and his daughter.

Macron told reporters during a visit to central France that information shared by British intelligence services confirms Moscow's involvement in the attack. He formally backed Prime Minister May's accusations earlier Thursday after the two leaders spoke by phone. His office issued a statement saying Macron shares the British's leaders view that "there is no other plausible explanation" for the incident.

A spokesman for Prime Minister May says she will travel to Salisbury later Thursday to speak with residents and officials.