North Korea tightens grip on phone SIM cards used by tourists

In a move to limit access to the internet, North Korea allows mobile phone SIM cards used by tourists to be active only for the duration of their visit, tourism sources say.

Unlike North Koreans, foreigners visiting the isolated country can browse social media sites such as Facebook and Twitter freely, using the Koryolink domestic network.

Under a change made in July, North Korea would deactivate the card when a visitor left, ensuring that it could not be left for use by a resident, the sources said. It could then be reactivated when a visitor returned to the country.

"This basically means in practical terms that if someone leaves the country they can't simply leave their phone with a local friend and have them use the internet," said one source.

The move could be linked to a broader crackdown on the exchange of information in North Korea, and according to the source appeared to have been government-led.

More than 2.5 million North Koreans use the Koryolink network to make calls and browse an internal, heavily monitored domestic internet. Foreigners can also use the network, but on a separate cell network that connects to the global internet. It was not clear if the new rule applied to contracts held by long-term residents or foreign diplomats.