The Philippines' new president is waging a drug war that has killed nearly 1,800 people

Protesters gather at Rizal Park during a rally to oppose the burial of the late Philippine dictator Ferdinand Marcos at the Heroes' Cemetery in Manila, Philippines, Sunday, Aug. 14, 2016. It was the biggest gathering so far since President Rodrigo Duterte ordered the burial of Marcos with full military honors and with the opposition announcing its plan to file a petition with the Supreme Court. (AP Photo/Bullit Marquez)
Protesters gather at Rizal Park during a rally to oppose the burial of the late Philippine dictator Ferdinand Marcos at the Heroes' Cemetery in Manila, Philippines, Sunday, Aug. 14, 2016. It was the biggest gathering so far since President Rodrigo Duterte ordered the burial of Marcos with full military honors and with the opposition announcing its plan to file a petition with the Supreme Court. (AP Photo/Bullit Marquez)

(Protesters gather at Rizal Park during a rally to oppose the burial of the late Philippine dictator Ferdinand Marcos at the Heroes' Cemetery in Manila, Philippines, on August 14. It was the biggest gathering so far since President Rodrigo Duterte ordered the burial of Marcos with full military honors and with the opposition announcing its plan to file a petition with the Supreme Court. (AP Photo/Bullit Marquez)syndication.ap.org)

When Rodrigo Duterte, the Philippines' president, took office in June, he announced a sweeping crackdown on drug trafficking in the island nation.

In the seven weeks since, nearly 1,800 suspected drug dealers have been killed.

Under Duterte, 712 drug suspects had been killed in police operations since July 1, while 1,067 killings were carried out by vigilante groups during the same time frame, National Police Chief Ronald dela Rosa, told a Philippines Senate committee on Monday, according to The New York Times.

Senators have been questioning police on the killings as part of joint hearings by the Senate's Committee on Justice and Human Rights and the Committee on Public Order and Dangerous Drugs. The senators also heard from witnesses accusing police of gunning down their family members for being involved in illegal drugs.

Sen. Leila de Lima, head of the Senate Justice Committee, said that she's concerned that some law enforcers and vigilantes are using the campaign against drugs to "commit murder with impunity," since many killings had not been carried out legally, the Associated Press reported.

"We want to know the truth behind the killings and violence. What really happened and why does this continue to happen?" De Lima said in Tagalog. "I'm not saying the killings and the use of lethal force have no legal basis, but too many have been killed for us to not be suspicious and to not question whether the rules of engagement are being followed."

Between July 1 and August 15, 665 people were killed by police while another 899 were murdered by unknown killers, Dela Rosa reported to the committee last week, according to The Washington Post — a drastically lower number than the one reported on Monday.

Police didn't explain the sudden increase in deaths over the past week, but senators are expected to question them about the tally on Tuesday.

Relatives of slain people cover their faces as they attend a Senate hearing investigating drug-related killings at the Senate headquarters in Pasay city, metro Manila, Philippines August 22, 2016. REUTERS/Romeo Ranoco
Relatives of slain people cover their faces as they attend a Senate hearing investigating drug-related killings at the Senate headquarters in Pasay city, metro Manila, Philippines August 22, 2016. REUTERS/Romeo Ranoco

(Relatives of slain people attend a Senate hearing investigating drug-related killings at the Senate headquarters in Manila.Thomson Reuters)

The spate of killings has alarmed human-rights groups, including UN-appointed human-rights experts who have urged the country to stop the killings.