European Central Bank chief Mario Draghi said Thursday it was "uncontroversial" that some form of debt relief for Greece -- whose debts amount to 180 percent of economic output -- was "necessary."

"Debt relief is necessary, it's uncontroversial," Draghi told a news conference, adding that the key issue was what form such relief could take. That would be the focus of discussions between Greece and its creditors in coming weeks, he added.