"Courageous decisions" are needed for Greece, the International Monetary Fund's (IMF) new managing director, Christine Lagarde, told reporters in Washington on Wednesday.

Lagarde also appealed to Greek political parties to cooperate amongst themselves, following the example of Ireland and Portugal. She also announced that the IMF will meet on Friday to discuss the next round of support for Greece.

"There is an IMF board meeting, which is scheduled for Friday, at which we shall consider the fourth review and eventually the payment of the fifth tranche that falls due," the former French finance minister said.