"The situation is clear: If there is a strong commitment from the Europeans to do whatever it takes to back Greece, the IMF will pay the money. And I can tell you there will be such a commitment," one senior euro zone source told Reuters.

The IMF had said disbursement of more money was contingent on a plan being finalized to guarantee Greece's funding needs into next year.

In Paris, Zhu Min, a special advisor to the IMF's managing director, said the Fund was deeply concerned by the latest political turmoil in Greece but stood ready to help if the government could win consent for its austerity plan.