Britain and the United States imposed sanctions Friday on men they said were Russian intelligence operatives responsible for the poisoning one year ago of Kremlin critic Alexey Navalny.
The two countries targeted seven Russians with sanctions and issued a joint statement warning Russia about chemical weapons.
Washington separately imposed sanctions on another two men and four Russian institutes it said were involved in chemical weapons research or what it described as an assassination attempt against Navalny.
Navalny was flown to Germany for medical treatment after being poisoned in Siberia on August 20, 2020, with what Western experts concluded was the military nerve agent Novichok.
Moscow has rejected their findings and accused the West of conducting a smear campaign against it.
"The sanctioned individuals are directly responsible for planning or carrying out the attack on Mr. Navalny," a Foreign Office statement said.
British Foreign Minister Dominic Raab said the move was a warning to Russia.
Call for investigation
"We are sending a clear message that any use of chemical weapons by the Russian state violates international law, and a transparent criminal investigation must be held," he said.
The sanctions will affect those people named who have overseas assets.
The British document listed Alexey Alexandrov, Vladimir Panyaev, Ivan Osipov, Vladimir Bogdanov, Kirill Vasilyev, Stanislav Makshakov and Alexei Sedov. It said they were all members of Russia's FSB security service and were either directly or indirectly involved in the poisoning.
The U.S. Treasury later said it was imposing sanctions on the same seven men and two additional Russian officials it said were involved in the poisoning: Konstantin Kudryavtsev and Artur Zhirov.
It also targeted the FSB Criminalistics Institute, a lab where most of those implicated in the attack worked, and the Russian defense ministry's State Institute for Experimental Military Medicine.
The State Department also imposed sanctions on two other Russian military scientific institutes involved in chemical weapons, it said.
Neither the Kremlin nor any of those named offered any immediate comment.
Phone, travel records cited
The British government cited evidence including phone and travel records showing some of the operatives were present in the Siberian city of Tomsk at the time of the poisoning.
For others it said there were reasonable grounds to suspect that, because of their positions in the intelligence service, they had "responsibility for, provided support for or promoted the actions of the operatives who carried out the operation."
Navalny was jailed for parole violations on what he said were politically motivated charges when he flew back to Russia earlier this year from Germany.
"We call on Russia to comply fully with the Chemical Weapons Convention, including its obligations to declare and dismantle its chemical weapons program," the joint U.S.-British statement said.
"We remain determined to uphold the global norm against the use of chemical weapons."