Dmitry Peskov spoke in response to comments by Syrian Foreign Minister Walid al-Moallem, who denied reports that Russian combat troops were fighting with Syrian troops, but said Syria would ask for Russia's help if needed.
If such a request is made, it will be "discussed and considered," Peskov said.
Al-Moallem, speaking in an interview on Syrian television late Thursday, said for now the Syrian army was capable of fighting on its own and what it needed from Russia was more ammunition and better weapons. He said Russia has "stepped up the pace" of those deliveries.
The United States has expressed concern about the ongoing Russian military buildup in Syria, which it believes is aimed at propping up Syrian President Bashar Assad.
Russia has called for a broad coalition to fight the Islamic State group, and Foreign Minister Sergey Lavrov on Thursday urged Washington and its allies to engage the Syrian government as a "partner" in this fight.
Russia sees the Islamic State group as posing a direct threat to its own security because of the high number of Russian citizens who have joined the terror group. The concern is that after gaining experience in Syria and Iraq, some could return to carry out attacks on Russian territory.
On Friday, Gen. Sergei Smirnov, deputy chief of the FSB intelligence agency, said Russia now has information that 2,400 Russian nationals have joined the Islamic State. That is considerably higher than the estimate of 1,700 that Smirnov gave in April.