MANILA (Reuters) - The Philippine government made another attack on Thursday (Sept 1) on a senator who is leading an inquiry into a spate of killings unleashed by President Rodrigo Duterte's "war on drugs", saying evidence she was linked to drugs was "overflowing".

Justice Minister Vitaliano Aguirre told reporters two former members of Senator Leila de Lima's staff and a third person, a prisoner in a penitentiary, had made sworn statements linking the senator to the drug trade.

"What they have provided is volunteered information," Mr Aguirre said. "It is not true that the evidence are being manufactured against her. These information are just overflowing."

Senator de Lima has denounced the government's attacks on her as "madness" and she has appealed to Mr Duterte to stop the string of bizarre accusations and insults against her. On Thursday, she denounced government "harassment" of her and said it was fabricating evidence against her.

About 2,400 people have been killed in Mr Duterte's drug war since he came to power two months ago, according to police figures. Police say the toll is a result of drug dealers resisting arrest or gang feuds.

Sen De Lima set up a Senate inquiry into the killings and held the first hearings last month.

Sen De Lima was justice minister for six years in former President Benigno Aquino's government and won a seat as a senator in May elections.

She told Reuters in an interview this week she had no fears for her life because it would be clear who was to blame if anything happened to her, but she had been warned by people close to Mr Duterte to stop questioning the extra-judicial killings.

Mr Duterte won the May election on a promise to wipe out drugs and dealers.