The State Duma approved in a third and final reading Friday a bill that will expand the powers of the Federal Security Service to allow it to issue warnings to people whose actions "create the conditions for a crime."
No definition of those actions is provided in the bill, stirring fears of possible abuse among human rights activists.
The Duma passed the bill in a vote of 354-96, with deputies from the Communist and A Just Russia parties voting against it.
The Federation Council is expected to approve the bill Monday, it said on its web site. The legislation will then go to President Dmitry Medvedev to be signed into law.
Medvedev defended the bill at a news conference with German Chancellor Angela Merkel last week, calling the changes a domestic security matter.
But human rights group Memorial denounced it, comparing it in a statement with a 1972 decree that allowed the KGB, the FSB's predecessor, to warn dissidents who went public with their views to not engage in "anti-social activities that contradict national security."
Three activists with the liberal opposition Yabloko party were detained Friday as they distributed leaflets opposing the bill outside the Duma, Yabloko said.
The Duma approved a total of 24 bills on Friday, its last working day before adjourning for the summer recess. Deputies passed an all-time-record 249 bills in the spring session, the Duma's web site said.