President Rodrigo Duterte declared on Monday he is now an enemy of embattled Chief Justice Maria Lourdes Sereno as he called Congress to immediately impeach her.

Duterte issued this statement following Sereno's challenge to him to explain to the people that the quo warranto petition Solicitor General Jose Calida filed before the Supreme Court to remove her from office was unconstitutional.

Duterte, who is a lawyer, reiterated he is not into habit of going after the opposition.

Despite Duterte's denial he was not behind the move to remove her from office, Sereno kept on insisting that Calida has his blessing.

"If you are insisting, then count me in. Count me in. And I will egg Calida to do his best," he said.

"So I'm putting you on notice that I am now your enemy. And you have to be out of the Supreme Court. I will see to it that after that then I'll request Congress, go into the impeachment right away," he said.

"Because the two entities can hear it simultaneously. They can proceed with the quo warranto. The quo warranto is Supreme Court, impeachment is Congress. So that I’d like to ask Speaker ( Pantaleon) Alvarez now, kindly fast-track the impeachment. She is bad for the Philippines," Duterte stressed.

Aside from a petition that Calida filed before the high court to invalidate Sereno's appointment, there is a pending impeachment complaint before the House of Representatives filed against her for alleged betrayal of public trust, violation of the Constitution, commission of high crimes, and corruption.

Specifically, she allegedly failed to submit her statements of assets, liabilities and net worth to the Judicial and Bar Council when she applied as the chief magistrate in 2012, among others.

Sereno said she is ready to face the impeachment trial before the Senate. Celerina Monte/DMS