Philippine President Rodrigo Duterte has said he would impose martial law if the drug problem became "very virulent", just a month after dismissing as "nonsense" any suggestion he might do so, Reuters reports. Duterte has made a brutal war on drugs a central pillar of his administration since he took office in the middle of last year. Since July, more than 6,000 people have been killed in the anti-drug campaign, in both police operations and unexplained killings by suspected "vigilantes". More than 1 million drug peddlers and users have been arrested or have surrendered to authorities.