A Filipino lawyer has presented documents to the International Criminal Court which he says contain evidence of the alleged involvement of President Rodrigo Duterte in extrajudicial killings of suspected drug dealers and other crime suspects.

Lawyer Jude Sabio presented a 77-page file outlining the allegations to prosecutors Monday morning.

The court receives many such communications about alleged crimes from around the world and prosecutors are not obliged to open preliminary investigations based on them. However, Sabio's filing comes after ICC Prosecutor Fatou Bensouda said last year that she was "deeply concerned" by reports of killings in the Philippines.