A US ban on its citizens travelling to North Korea has come into effect, at a time of heightened tensions over North Korean missile launches.

The new rule was announced after US student Otto Warmbier died after being released from prison in North Korea.The State Department said it was necessary "due to the serious and mounting risk" of detention.

Any US citizen breaking the rules may face criminal penalties and have their passports revoked.

The State Department would only grant permission to US citizens to go to North Korea "under very limited circumstances", such as for journalism or humanitarian work.
Tour operators have suggested that up to 1,000 Americans visit North Korea every year, making up about a fifth of Western tourists. The vast majority of visitors are Chinese.

On Thursday, tour operators flew out their last American tourists from Pyongyang.
http://www.bbc.com/news/world-asia-41120738