European Stability Mechanism (ESM) fund chief, Klaus Regling, and Euro Working Group (EWG) head, Thomas Wieser, both maintain that Greece cannot remove the International Monetary Fund (IMF) from its economic bailout on Sunday. Regling added that the possibility of a Greek eurozone exit remains if reforms are not made.

Both men were categorically against the IMF’s exit from Greece. “There has to be a financial contribution because the IMF, according to the ESM Treaty and to the agreement in the July summit, should be part of the program also financially,” said Regling in an interview with Greek weekly newspaper To Vima.

Regling’s comments come following arguments made by Prime Minister Alexis Tsipras concerning the IMF’s participation that he deemed “not necessary” in the cuntry’s third bailout. Tsipras highlighted the IMF’s “unconstructive” position.

Regling, however, warns that if the IMF decides not to participate then this could be a big problem for Greece.