Moscow (AFP) - Russia's air force hit more than 60 "terrorist targets" in Syria over the past 24 hours, Moscow's military said Friday, significantly ramping up its bombing campaign in the war-torn country.
"Sixty-seven sorties have been carried out from the Hmeimim air base" in Syria, the deputy head of the Russian General Staff, Lieutenant General Igor Makushev, told reporters.
"Su-34M and Su-24SM warplanes hit 60 terrorist targets," he added.
According to intercepted radio communications, two high-ranking Islamic State field commanders and several hundred militants were killed, the Russian military said.
Last week, Moscow made a dramatic entry in the multi-front conflict in its Soviet-era ally Syria, saying it needed to stop Islamic State jihadists before they cross into Russia, which has a large Muslim minority.
Washington and its allies have said Moscow has also been targeting Western-backed moderate rebel groups as it supports an offensive by forces loyal to President Bashar al-Assad.
Makushev said militants "have sustained significant casualties and been forced to change their tactics," seeking refuge in towns and villages, stressing that Moscow would increase the intensity of the strikes.
The defence ministry had said earlier that 27 "terrorist" targets have been hit on Thursday.
On Wednesday, Russian warships from the Caspian Sea fleet joined in the strikes with a volley of cruise missiles, the first time Moscow has used cruise missiles.
Makushev said Russia has been bombing command posts and communication centres, ammunition depots as well as training camps in Raqa, Latakia, Hama, Idlib and Aleppo.
Russia said its warplanes also dropped precision guided bombs on a command post in IS stronghold Raqa, killing two senior IS field commanders and some 200 fighters.
The strikes also destroyed six command posts and communication centres, six ammunition depots, 17 training camps, three underground targets in Latakia, two multiple artillery rocket systems and 17 vehicles and armoured vehicles, among other targets, the military said.
"In the vicinity of Aleppo, a strike hit a militants' base and ammunition depot set up in the building of a former prison," Makushev.
"As a result, some 100 militants and an ammunition depot have been destroyed."
Despite the Russian action, the Islamic State group advanced Friday to the outskirts of Aleppo in an offensive that also took the jihadists to within a few kilometres (miles) of regime troops defending the city, said Rami Abdel Rahman of the Syrian Observatory for Human Rights.