Russian Foreign Minister Sergei Lavrov expressed "regret" in a phone call with U.S. Secretary of State Rex Tillerson on April 21 regarding the United States' opposition to a Moscow-backed plan to investigate an alleged chemical attack in Syria.
During the call with Tillerson, which was "initiated by the American side," Lavrov raised a joint Russian-Iranian probe proposal made at the global chemical arms watchdog, the Organization for the Prohibition of Chemical Weapons (OPCW), a Russian Foreign Ministry statement said.
The U.S. State Department issued a brief statement saying the diplomats "discussed a range of…topics, including the OPCW's investigation into Syria's use of chemical weapons on April 4."
"The secretary reiterated his support for the OPCW's existing investigative mechanism," the statement said.
Western nations have accused the Syrian regime of carrying out the suspected April 4 air strike, but Moscow and Tehran, allies of Syrian President Bashar al-Assad, have sought to clear Damascus of blame.
The incident left 87 people, many of them children, dead.
During the April 21 call, Lavrov expressed "regret" that the United States had spoken out at the OPCW against "Russia's initiative to send inspectors to Syria to verify allegations of the use of sarin in the town of Khan Sheikhun on April 4 and the presence of chemical-warfare agents at Shayrat Air Base in Syria," according to the Russian statement.
Lavrov and Tillerson "agreed to examine once again the possibility of carrying out an objective investigation into the incident under the auspices of the OPCW," the Foreign Ministry wrote.
The OPCW on April 20 "overwhelmingly" rejected the Russian-Iranian move to launch a new investigation into the suspected chemical attack in Syria, delegates said, backing a probe that is already under way.