Rodrigo Duterte, the Philippine president whose controversial war on drugs has killed thousands over the past two years, said on Monday that he used marijuana to stay alert in meetings, but then claimed he was joking.

His attempted humour was lost on human rights activists who denounced the quip as disrespectful to the families of drug users, dealers, and innocent bystanders who have been gunned down in the name of tackling illegal drugs since Mr Duterte rose to power in June 2016.

The victims have mainly been linked to shabu - a slang term for methamphetamine – but the use and sale of marijuana is also illegal under Philippine law.

“I use marijuana to stay awake,” said the president, 73, while speaking at a ceremony to honour Philippine diplomats. He made the comment while complaining about the gruelling schedule of the Association of Southeast Asian Nations (Asean) summit in Singapore last month.

Mr Duterte’s office had admitted he missed events at the Asean meeting to take “power naps”. He later explained that his hectic schedule was a “killing activity” at his age.