The entire police force in part of the Philippine capital is to be relieved of duty, after the controversial deaths of three teenagers.
Manila police chief Oscar Albayalde said 1,200 officers from the Caloocan district would be retrained and then assigned to other units.
The move comes amid growing scrutiny of police operations amid President Rodrigo Duterte's anti-drugs war.
The most high-profile case involved a boy killed in Caloocan on 16 August.
Police say Kian Loyd Delos Santos, who was 17, ran from them and then opened fire, so they shot him.
But his parents say he had no involvement in drugs. A witness said police tried to force a gun into his hand and CCTV footage shows a boy, said to be him, being dragged away by police, contradicting claims he ran.
A second case involved the death of Carl Arnaiz, a 19-year-old accused of trying to rob a taxi driver. Police said he fired at them but the taxi driver said he saw him alive in police custody. A 14-year-old boy, last seen with Arnaiz, was later found dead.
Several policemen are now under investigation and the Senate is currently conducting an inquiry into the teenagers' deaths.
Mr Albayalde said the police in Caloocan would be retrained in batches, and all would be temporarily replaced by personnel from a regional security unit.
"They will be retrained and they'll be reassigned to other stations here in Metro Manila. They will not be able to go back to their position or their assignment in Caloocan," local media quoted him as saying.
Mr Duterte was elected on a promise to tackle the country's drug problem but his brutal crackdown has been highly controversial.
Police figures say 3,800 suspects have been killed in anti-drugs operations since he took office. Several thousand more unexplained killings have also been attributed to the crackdown.
But rights groups have voiced serious concerns over extrajudicial killings. Earlier this year, Mr Duterte briefly suspended his crackdown to clean up the police force after officers seized a South Korean businessman under the guise of a drugs raid, killed him and sought a ransom from his family.
Many Filipinos support the crackdown. But the recent deaths have generated debate and some protests.
On Thursday night, Catholic churches rang their bells for five minutes to mark those who had died and call for the killing to stop. This is to continue for 40 nights.
"We cannot allow the destruction of lives to become normal. We cannot govern the nation by killing," Archbishop of Manila Cardinal Luis Antonio Tagle said in a statement last week announcing the campaign.