WhatsApp accused Moscow of trying to block millions of Russians from accessing secure communication after calls on the messaging app were restricted, as Russia promotes home-grown social media platforms and seeks greater control over the country's internet space.

WhatsApp is generally inaccessible in North Korea which has blocked Facebook, YouTube, Twitter and other platforms since 2016. North Korea has one of the world's most strictly controlled internet systems. Russia started restricting WhatsApp from Wednesday. It had clashed with foreign tech platforms for several years over content and data storage.

Russia plans to restrict some calls on WhatsApp and Telegram, saying the apps don't cooperate with the government to stop "deceit and fraud."