Russia's air force hit 60 Islamic State targets in Syria over the past 24 hours and killed around 300 militants, the Defense Ministry said on Friday, in Moscow's most intense raids yet since it first launched strikes on Syria 10 days ago.

In the previous updates, the Moscow had been reporting hitting about 10 targets daily. The increased pace of attacks was aimed at preventing militants from re-grouping and dispersing in populated areas, the ministry said.

The ministry said in a statement that air force jets used KAB-500 precision guided bombs to destroy a headquarters of the Liwa al-Haqq militant group in Syria's Raqqa province.

The ministry, citing intercepted radio communications, said the raid killed two senior Islamic State field commanders and some 200 militants there.

Liwa al-Haqq is not connected to Islamic State, so it was not clear what the two field commanders were doing at the group's base.

The ministry also said it destroyed an Islamic State base and munitions storage set up in a former prison near Aleppo, killing another 100 militants.

A monitoring group said on Friday Aleppo had seen intensified fighting as Islamic State seized villages close to the city from rival insurgents.

Other targets identified by the Russian ministry as having been struck in the past 24 hours included militants' training sites in the Latakia and Idlib provinces.

The ministry said its SU-34, SU-24M and SU-25CM fighter jets carried out 67 sorties over the past 24 hours.