Duterte won the election in May on a platform of crushing crime, but his incendiary rhetoric and advocacy of extrajudicial killings have alarmed many who hear echoes of the country's authoritarian past. He has been nicknamed "The Punisher." 

Oscar Albayalde, police chief for the Manila region, said five drug dealers were killed Sunday in a gunbattle with police in a shanty town near a mosque not far from the presidential palace. 

"My men were about to serve arrest warrants when shots rang out from one of the houses in the area," Albayalde told reporters, saying officers returned fire and killed five men. 

Four guns and 200 grams of crystal methamphetamine were recovered. Three other "drug dealers" were killed in other areas in Manila on Sunday and 22 were killed in four areas outside the capital. 

More than 100 people have died, mostly suspected drug dealers, rapists and car thieves in stepped up anti-crime police operations since the election on May 9.