India, April 10 -- Several dozen people lined up outside a presidential administration building on a sunny spring weekend in central Moscow as police stood nearby and watched them closely.

The people were lodging complaints about the government's intensifying crackdown on the internet that has seen regular shutdowns of cellphone internet connections, blocked popular messaging apps and cut access to thousands of other websites and digital services.

It was the latest sign of the growing anger and frustration over the restrictions that have disrupted the daily lives of Russians, hurt businesses and drawn criticism even from Kremlin supporters.

Knowing that any unauthorized demonstrations are harshly suppressed, activists have tried to org...