A spokesman for the Russian president says Vladimir Putin has signed into law controversial counter-terrorism amendments that have sparked alarm among rights activists.

The amendments that the parliament adopted last month include introducing prison sentences for failure to report a grave crime and doubling the number of crimes for which Russians as young as 14 can be prosecuted. Another forces telecommunications companies to store logs and data for months, a measure that threatens to eat all of the companies' profits.

In an apparent concession to the disgruntled businesses, Dmitry Peskov told reporters on Wednesday that Putin also signed a decree instructing the government to oversee and if necessary modify the implementation of the amendments in the light of possible "financial risks."