Russia has claimed that almost 88,000 militants have been killed in Syria since Moscow intervened in backing government forces three years ago.
"Over the course of the operation, a total of more than 87,500 rebels have been eliminated, 1,411 settlements have been liberated and more than 95 per cent of Syria's territory," Russian Defence Minister Sergei Shoigu said on Saturday.
Moscow's air forces started launching strikes in support of President Bashar Al Assad's government in September 2015.
"Most of the rebels have been liquidated," Mr Shoigu was quoted as saying at a forum in Singapore in a ministry statement. More than 40,000 bombing missions have taken place, hitting about 120,000 targets of "terrorist" infrastructure, Mr Shoigu said.
The defence minister said that "Syrian armed forces currently control territory where more than 90 per cent of the population lives".
Experts say the claims were yet another act of Russian propaganda.
"Where does one even get a number like that? Is it simply tallying total claimed death tolls from all reported strikes, for example?," Aymenn Al Tamimi, fellow at the Middle East Forum told The National.
"The statement talks about 95 per cent of Syria’s territory as ‘liberated’. The Syrian government certainly would not share that view in light of areas outside its formal control that have a US troop presence," he said.
The Syrian Observatory for Human Rights, a UK-based war monitoring group, says some 365,000 people have been killed during the seven-year civil war.
Mr Shoigu's comments came as Washington denied claims made by Russian President Vladimir Putin that ISIS has taken nearly 700 people as hostages and are carrying out daily executions.
Mr Putin claimed that European and American nationals were taking from a refugee camp in a US-controlled area.
At an international policy forum in Sochi, Mr Putin said “they have been recently expanding their area and took about 130 families hostage, which accounts for about 700 people”.
The Russian leader said the militants have put forth demands, which he did not specify, and have warned that they would kill 10 people a day if the demands are not met.
“They killed 10 people the day before yesterday,” he said. “They are now carrying out their threats.”
State news agency Tass Wednesday cited an unnamed “diplomatic-military source” as saying the hostages were seized in a raid on a refugee camp and were demanding Syria free ISIS members.
Yet, the Pentagon expressed scepticism, saying that it has "no information" that supports Mr Putin's claim of such a large number of hostages.
"While we have confirmed that there was an attack on an IDP (internally displaced persons) camp near (Deir Ezzor) last week, we have no information supporting the large number of hostages alleged by President Putin and we are sceptical of its accuracy," Pentagon spokesperson Commander Sean Robertson said.
"We are also unaware of any U.S. nationals located in that camp," Mr Robertson said.
Elsewhere, Syrian state media and SOHR reported on Saturday that six hostages, including women and children, held by ISIS were freed. They were captured when the terror group attacked Syria's Sweida city three months ago.
The insurgents released the first group of hostages after talks with local authorities, according to the Syrian Observatory for Human Rights.
ISIS killed more than 200 people when it staged multiple attacks and overran villages in southwestern Syria in July.