The strikes took place in the Latakia, Aleppo, Hama and Damascus provinces.
The damage the Russian SU-34 jets caused to the underground bunkers was especially significant, Defense Ministry spokesman Major General Igor Konashenkov said.
They hit the terrorists’ underground infrastructure in Homs, which had allowed the militants to move undetected and increase their effectiveness in combat.
The well-funded Islamic State (IS, formerly ISIS/ISIL) has been hiding whole weapons caches underground, which included explosive devices for carrying out terrorist attacks.
A small missile factory was among the objects destroyed. However, these underground bases and conduits are believed to be widespread across Syria, so more work needs to be done, Konashenkov says.