MANILA - Vice President Leni Robredo on Thursday expressed confidence that President Rodrigo Duterte will stay true to his promise of upholding the rule of law in his war against drugs.

Speaking to reporters, Robredo noted that Duterte gave that assurance during his inauguration, where he stressed that he knows "what is legal and what is not."

"Tingin ko naman hindi niya naman ico-condone yung parang vigilante-style na execution," said Robredo.

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She, however, expressed alarm over the spate of killings of alleged drug pushers and users.

"Nakakabahala lang kasi marami na talaga," she said. "Ang nakakabahala dito yung baka nagcre-create na tayo ng culture of people taking law into their own hands, na hindi dapat tayo papayag."

She pointed out that it is within the mandate of the executive to allow the Department of Justice (DOJ) or the Department of Interior and Local Government (DILG) to look into these cases, stressing the importance of giving due process to the accused.

She said it is also within the mandate of Congress to conduct a similar investigation.

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"Kasi hindi naman pwedeng pabayaan. Kasi kapag hinayaan natin yung mga tao na to take the law into their hands, baka maraming inosente na madamay," she said.

"Kaya naman tayo may mga courts kasi sila yung final arbiter kung sino ang nagkasala. Kasi kung tayo-tayo lang ang magdedesisyon, talagang grabe na yung disorder na mangyayari," she added.