April 13 (UPI) -- Russia's top diplomat said Friday that Moscow has proof that the suspected chemical attack in Syria last weekend was staged by special agents of a foreign country.
"And special services of a country, which is now seeking to be in the first ranks of the Russophobic campaign, were involved in this," Lavrov said.
Although he didn't name the country the agents come from, the top Kremlin diplomat could be hinting at the United States, Britain or France.
Lavrov also said Russian specialists who examined the attack found no trace of chemical weapons.
Damascus has invited a team from the Organization for the Prohibition of Chemical Weapons to visit Eastern Ghouta. They are due to arrive in Syria Saturday to investigate.
"The mission of the OPCW has set off to Syria not so quickly and without abundant enthusiasm but under our and Syrian pressure," Lavrov said.
Friday's news came as Trump continued to weigh a response to the attack, which could involve military intervention.
"You shouldn't be partners with a Gas Killing Animal who kills his own people and enjoys it!" Trump tweeted Thursday.
Syria has denied using chemical weapons and Russia has blamed the White Helmets -- a volunteer group inside rebel-held areas in Syria.
"The notorious White Helmets, who operate as part of terrorist groups, staged and filmed a chemical weapons attack on civilians in the town of Douma," Russian Lt. Gen. Viktor Poznikhir said this week.
NBC News reported Thursday the United States has urine and blood samples that tested positive for chemical weapons, including chlorine gas and another nerve agent.
Assad is believed to have a stockpile of the nerve agent sarin, and has previously used a mixture of sarin and chlorine in past attacks.