BALASHIKHA, Russia (Reuters) - A major with an elite unit from Russia’s interior ministry was killed in Syria last month, several of his former comrades told Reuters on Wednesday, though Russian officials have not acknowledged his death.

A view shows the grave of Russian serviceman Sergei Chupov at a cemetery in the Balashikha district of the Moscow region, Russia, March 23, 2016. REUTERS/Maria Tsvetkova

The death would bring to six the number of Russian servicemen known to have been killed in Syria during the Kremlin’s five-month military campaign, which it said last week it was winding down.

The death of Sergei Chupov, 51, was first reported by the Conflict Intelligence Team, a group of Russian bloggers who use social media to track Russian military engagements abroad.

Reuters spoke independently to several former colleagues of Chupov, who confirmed that he was killed in fighting in Syria. Reuters also visited the cemetery outside Moscow where Chupov is buried.

Funeral wreaths and a modest iron cross with a wooden crucifix adorn the fresh grave, with a picture of Chupov wearing uniform and medals. The date of his death marked on the grave, Feb. 8, matches the date in other accounts of his death.

“I know Chupov was a negotiator in Syria and was killed by a direct hit from a mortar shell,” Radik Belov, who said he served under Chupov’s command in a reconnaissance platoon in the 1990s, told Reuters.

The Russian defense ministry, which oversees the Russian operation in Syria, and the interior ministry, did not respond to Reuters questions about Chupov. A Kremlin spokesman said he had not heard about the case.

There were no details about what Chupov was doing in Syria. His former comrades said he was a long-standing officer with experience of combat. He served with the Interior Ministry troops, an elite force who have in the past been involved in fighting in Russia’s restive Chechnya region.

SPECIAL FORCES

Russia has for months said its role in Syria is restricted to air strikes, advising and training Syrian government forces, search and rescue missions for downed aircrew, and protecting Russia’s bases.

However, Russia’s Interfax news agency on Wednesday quoted the commander of Russia’s contingent in Syria, Alexander Dvornikov, as saying that Russia had special forces in Syria who were involved in reconnaissance of targets for air strikes and “other special tasks”.

At the cemetery in the town of Balashikha, four men in their thirties and forties, who said they had served under his command, left a glass of brandy and a slice of bread at his grave, a Russian tradition.

They said they were all ex-servicemen but declined to give their names. They referred to Chupov as their commander and mentor. He was “a true Russian officer” said one of the men. Another described him as someone “who deserved to be a hero”.

They said they did not want to go into details because Russia has many enemies and the death of a Russian soldier in Syria could be used against Moscow.

Asked about the bloggers’ report, Kremlin spokesman Dmitry Peskov told a teleconference with journalists: “I have heard nothing about it. I don’t know ... on what sort of information it’s based.”

President Vladimir Putin last week ordered the withdrawal of the bulk of Russian forces in Syria, saying they had achieved most of their objectives.

At a Kremlin ceremony a few days later to decorate officers for the Syria mission, Putin broke four months of official silence about the death of a Russian soldier, Fyodor Zhuravlyov, bringing the official death toll Syria to five.

The Conflict Intelligence Team, citing social media posts and accounts of people who knew him, said Chupov graduated from a prestigious military school in then Soviet Kazakhstan, and served in Afghanistan and Chechnya.