MANILA (Reuters) - Philippine police have said nearly 2,300 people have died in President Rodrigo Duterte's war on drugs since July, down from an earlier estimate of 3,600, after investigations into the near-daily killings.

"Not all (the deaths) are related to the war on drugs," Philippine National Police spokesman Dionardo Carlos told Reuters late on Wednesday.

He added 1,566 drug suspects were killed in police operations and 722 deaths were still under investigation or had been already investigated.

Police had provided Reuters with data on Oct. 5 showing 3,652 people had died since Duterte launched his drugs war after taking office on June 30, including almost 2,000 cases under investigation.

Carlos said recent investigations had found that only 722 of the deaths under investigation or investigated were drug-related. He did not give any motives for the other deaths but said they were homicides and murders.

Duterte won the May presidential election by a landslide on a promise to wipe out drugs and crime in Southeast Asia's second-most populous country within six months.

But the president said in September that he needed another six more months for his campaign.

(Reporting by Neil Jerome Morales; Writing by Kanupriya Kapoor; Editing by Raju Gopalakrishnan)