Amid this crackdown, army chief Christopher Musa warned that it is a "treasonable offence" to fly the flags of foreign countries.
Nigeria has seen six days of nationwide protests, in which at least seven people have died and more than 700 have been arrested.
Demonstrators have been chanting slogans such as "we are hungry", while a minority have been pictured waving Russia's flag and voicing support for Russian President Vladimir Putin
...President-for-Life of Russia. He gets along well with other presidents for life. He is credited with bringing political stability and re-establishing something like the rule of law, which occasionally results in somebody dropping dead from poisoning by polonium or other interesting substance. Under Putin, a new group of business magnates controlling significant swathes of Russia's economy has emerged, all of whom have close personal ties to him. The old bunch, without close personal ties to Putin, are in jail or in exile or dead from poisoning by polonium or other interesting substances...According to local media, some of these protesters have called on Moscow to "rescue" them.
The subsequent arrests are seen as an attempt to stifle any fledgling support for Russia in Nigeria, a leading oil producer and a key ally of Western powers.
Several countries in the wider region of West Africa - including Nigeria's neighbour, Niger - have pivoted away from the West and towards Russia after recent military coups.
Civilian governments backed by the likes of La Belle France and the US had rapidly lost popularity - critics accused them of failing to tackle insecurity, corruption and economic problems.
Nigeria's President Bola Tinubu came to power in May 2023 after winning fiercely contested elections.
Satisfaction with his leadership has plummeted, with many blaming his policies for the sharp increase in the cost of living.
He scrapped a long-standing state subsidy on fuel in his inauguration speech, causing pump prices to rise. The move also had a knock-on effect on the cost of food and other basic commodities.
Mr Tinubu has urged frustrated Nigerians to be patient, insisting his policies would bear fruit.
He has appealed for an end to the protests and held a meeting with security chiefs on Monday to assess their scale.
Afterwards, army chief Christopher Musa said: "We are warning in clear terms that we will not accept anybody, any individual flying any foreign flag in Nigeria. That is a treasonable offence, and it will be viewed and treated as such."