Philippine President Rodrigo Duterte's war on drugs had until three weeks ago driven the trade in crystal methamphetamine underground, according to residents and drug users in some of the slum areas of the nation's capital city.

As thousands of users and dealers were shot dead by police and vigilantes in the first seven months after Duterte came to power last June, open dealing in the drug, known here by its street name shabu, largely stopped. Instead, deals were done on the quiet between people who knew each other, maybe with a text message first.

But since Duterte ordered the Philippine National Police (PNP) to stand down from the drug war last month, after declaring the force "rotten to the core," the drugs trade has come back out of the shadows, more than half a dozen drug users and dealers in some of Manila's toughest areas said in interviews. Many spoke on condition that only their first names be used in this story.