An internet troll whose grossly offensive Facebook postings included threats to kill 200 US children has been jailed for more than two years after a judge heard how he spread terror in local schools.

A British internet troll has admitted threatening to kill 200 US citizens in Facebook posts which led thousands of children to stay off school.

A 24-year-old man has been charged with threatening to kill after allegedly posting on Facebook he would kill 200 people in America.