MANILA - Two senators on Monday nixed as "premature" Senator Leila de Lima's proposal for a Senate investigation on the spate of killings of drug suspects all over the country.

Sen. Panfilo Lacson, a former Philippine National Police chief, said it is too early for a Senate inquiry on the issue of killings of drug suspects.

"It's premature for the Senate to talk about summoning the [Chief PNP] and investigating the police for supposed summary killings when, as it appears at least for the moment, it's merely based on conjectures and suspicions and without sufficient basis," he said in a statement.

"Unless there's at least a testimony under oath that summary executions were indeed committed in the course of the police anti-drug operations, I'm afraid we will just embark on a fishing expedition."

On the other hand, Lacson also chided Solicitor General Jose Calida for saying that policemen could snub congressional inquiries about the killings.

PNP can snub Senate probe, says SolGen

"I think it's even more premature for Solgen to advise the CPNP [chief PNP] to ignore the Senate's summons if and when such investigation in aid of legislation is conducted. Wala pa yung actual na pinag-uusapan, pinag-aawayan na," Lacson said.

Similarly, Sen. Tito Sotto also said a Senate inquiry on the killings is premature.

In a text statement, he said the Commission on Human Rights (CHR) and the National Police Commission (NAPOLCOM) should be allowed to investigate first the alleged summary killings.

"He is right. At this point, we should allow the CHR and NAPOLCOM to do their investigations. I don't see any legislation we can discuss to necessitate a hearing. Perhaps later, pag meron na silang ire-report. Any Senate inquiry at this point is premature," he said.

For his part, Sen. Sonny Angara said he intends to participate in any inquiry the Senate will conduct regarding the killings of drug suspects as well as the growing drug menace.

"There is a war being waged against drug pushers who have threatened our peaceful and lawful way of life. I hope the Senate inquiry will support our law enforcers in this war as well as ensure human rights of all are respected. We do not intend to embarrass but rather support our law enforcement officials in their fight to keep our streets peaceful and protect our youth and our people from the drug menace," he said.

"We in the Senate must rally behind our law enforcers while also ensuring rights are protected."

Sen. De Lima, a former Justice Secretary and head of the Commission on Human Rights, earlier said there are "telltale signs" that some of the drug suspects being killed by law enforcers are victims of summary executions.

"Nakakaduda yung explanation na nanlaban, nang-agaw..." she said.

De Lima to SolGen: I will not be intimidated

She rejected the Solicitor General's claim that a complaint must be filed first before the Senate can open an investigation in aid of legislation.

Police have confirmed killing more than 110 suspects since President Rodrigo Duterte won the May 2016 elections, promising a law-and-order crackdown that would claim thousands of lives and fill funeral parlors.

A lawyer and a former prosecutor, Duterte has urged law enforcers to kill those they believe are involved in the drug trade, as well as other criminals.

As the official death toll has mounted, and other bodies not confirmed killed by police have been found with placards declaring them drug traffickers, human rights lawyers and some lawmakers have expressed deep concerns about the war on crime spiraling out of control.

In response to the criticism, Calida held a press conference on Monday at the PNP headquarters to insist on the legality of the police killings and to encourage more deaths of people suspected of being involved in the drug trade.

"To me, that is not enough," Calida said of the killings so far.

"How many drug addicts or pushers are there in the Philippines? Our villages are almost saturated (with drugs)."

One of the nation's top human rights lawyers, Jose Manuel Diokno, warned last week that Duterte had "spawned a nuclear explosion of violence that is spiraling out of control and creating a nation without judges."

Former Senator Rene Saguisag, a prominent human rights lawyer during the regime of dictator Ferdinand Marcos, also criticised Duterte's statements naming and shaming alleged drug lords and police officers ahead of a formal investigation.

"Do we still probe and have a trial as part of due process? Useless, it seems to me," Saguisag wrote in an online column last week. -- With a report by Agence France-Presse