MANILA, Philippines - Invoking poor health, Sen. Miriam Defensor-Santiago has resigned her post as judge of the International Criminal Court (ICC).

In a June 3 letter to Sang Hyun Song, president of the ICC, Santiago said she is quitting her post due to her chronic fatigue syndrome.

â€œPursuant to my commitment, I hereby confirm that the court should proceed on the basis that I am stepping down as elected judge,â€ she said.

â€œI will support the procedures of the Assembly of State Parties later this year, so that a replacement judge can be duly elected,â€ she added.

She furnished President Aquino a copy of her letter. She likewise notified Senate President Franklin Drilon and Foreign Affairs Secretary Albert del Rosario, and requested the Department of Foreign Affairs (DFA) to circulate her letter â€œwith thanksâ€ to all parties of the Rome Statute.

Santiago was â€œoverwhelmingly electedâ€ to the ICC based in The Hague, Netherlands in December 2011. She was elected to a nine-year term.

First Filipino, first Asian

She is the first Filipino and the first Asian from a developing country to be elected to the tribunal, which tries cases of genocide, war crimes and crimes against humanity.

She was scheduled to report to the ICC since last year. In September, she said she would file a parallel request for permission to report to the ICC when she recovers from her illness early this year.

But she also hinted that she might just back out from the post.

The senator was also unable to report for work at the Senate regularly due to her illness.

In June last year, an online petition asked the ICC to reject her election to the judicial body, saying she does not deserve the post for being â€œemotionally or psychologically unstable, prone to fits of uncontrollable rage, lacking in patience and empathy, ruthless with the feelings of fellow human beings, bereft of civility and uncaring about decorum.â€

â€œWe further submit that an individual who has admitted to having publicly lied and who has demonstrated partiality, prejudice, lack of principles and questionable integrity as a public official does not deserve to be a judge, much less a judge of the International Criminal Court,â€ the petition posted on change.org by US-based lawyer Rodel Rodis stated.

Santiago dismissed the petition as a black propaganda against her.