Fatou Bensouda told the German daily Sueddeutsche Zeitung that such steps would be possible for extremists whose home countries have signed on to the ICC's treaty.
"There is a lot of evidence that there are foreign fighters in the ranks of IS from countries that have signed the court's statute, including Jordan, Tunisia and European countries," she said.
"We could prosecute these suspects for war crimes and crimes against humanity."
Bensouda said she had already received files from the governments of Lebanon, Tunisia and Jordan and was "reviewing our options".
But she said that war was still raging in the countries where investigations were required and noted that it was increasingly difficult to fly out witnesses to testify.
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"More and more, we try to work with documents and not witnesses," she said.
IS has carried out widespread atrocities since seizing control of large parts of Iraq and Syria, executing five Western hostages and hundreds of locals.
The group on Sunday released a grisly new video showing the execution of 18 Syrian prisoners and US aid worker Peter Kassig.
Some 3,000 Europeans have joined the jihadists, EU counter-terrorism chief Gilles de Kerchove said in September.
The ICC is the world's only independent permanent tribunal to try cases of genocide, war crimes and crimes against humanity. It was established in 2002 and opened its doors a year later.