"There are Russian citizens in Syria, who went there on their own accord and with different goals", the statement said, adding that it was not the task of the ministry to assess the legitimacy of such decisions.
The US coalition on February 7 struck a formation attacking a position of the Syrian Democratic Force east of the Euphrates river in eastern Syria, killing about 100 people.
Many Russian nationals were reportedly killed in the strike, according to their relatives and paramilitary groups, as well as political organizations that published information about the casualties.
On Thursday, Russian Foreign Ministry spokeswoman Maria Zakharova said five Russian nationals were preliminarily confirmed to have been killed in Syria in the clash with the US -led coalition.
Mueller charges lawyer with lying about interaction with Rick Gates
FBI Director Robert Mueller speaks during a news conference at the FBI headquarters June 25, 2008 in Washington , DC. Alex van der Zwaan, the lawyer, is well-connected and represents the interests of a number of Russian oligarchs.
"They were given assistance for their return to Russian Federation where, as far as it is known, they are being treated at medical establishments", the ministry said.
The Russian Foreign Ministry said on Tuesday that several dozen Russian citizens and citizens of other countries in the former Soviet space had been wounded in recent clashes in Syria and were being treated in Russian hospitals. Meanwhile, in the Kremlin disown the dead in Syria the Russians.
As Russia's Defense Ministry announced earlier, the Syrian militia fighters came under the coalition's strikes in the province of Deir ez-Zor on February 7 due to actions uncoordinated with the Russian military.
A local Cossack leader Andrei Datsenko, who posted on Facebook that Mitin received his injuries in Syria, also later deleted his message.