According to the Russian constitution, we cannot strip anyone of citizenship," Putin told Mir television station.
"But we can cancel the decisions that served as the basis for obtaining Russian citizenship. We are holding consultations with our lawyers and I think that such decisions will be made in the very near future."
The comments come in the wake of a deadly attack on the Saint Petersburg metro by an alleged Russian citizen who was born in mainly muslim Kyrgyzstan in ex-Soviet Central Asia.
No one has claimed responsibility for the bombing, but the authorities say they are probing ties to Islamic State jihadists.
Putin said that nearly 10,000 people from ex-Soviet countries part of the Commonwealth of Independent States (CIS) were fighting in Syria, according to some estimates.
Other estimates put that figure at around 9,000 people, half of whom are Russian nationals, Putin said, adding that 5,000 of them hailed from Central Asia.
"The (terror) threat is very big and real," Putin said.
"We know it, we understand the scale of this threat and must do everything to minimise it."
Jihadists from IS - including foreign fighters from the ex-Soviet Central Asia and the Caucasus region - have repeatedly threatened an attack on Russian soil to avenge Moscow's military support of Syrian leader Bashar al-Assad.