Former British newspaper editor Piers Morgan, who is now a TV host for US network CNN, said he has become "increasingly angry" at the number of Americans killed in gun murders.
"In Britain we have between 30 and 50 gun murders a year," he explained. "In America they have 11-12,000 murdered with guns every year. Another 18,000 people kill themselves with guns every year."
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The 36-year-old has not been seen or heard from since Thursday evening.
Sophie Neville, cast as Titty as a young child in the 1974 classic Swallows and Amazons, is advising its modern-day adaptation.
At least two people are feared dead in the attack which is the latest on medical facilities in the war-torn country.