Medvedev has defended the law, saying earlier this month that its aim was to improve Russian legislation and had been drawn up on his personal orders.

"Every country has a right to fine-tune its legislation, including in respect to special services," he said.

The Kremlin has also said the law will help combat extremism and prevent illegal participation in anti-government activities such as protest rallies.

Under the 2000-2008 presidency of former KGB agent Vladimir Putin, the FSB dramatically increased its influence over Russian society.