Antonis Samaras, who is the head of Greece’s New Democracy party, was told by the president of the European Commission to quit playing ”political games” and to drop his refusal to pledge written support for Greek budget cuts as a condition for the next installment of international aid.

”For the European Union and IMF to support, they need to be sure that this is or a sustainable effort,” said commission president Jose Barrosom yesterday in Brussels in a press conference with Greek Premier Lucas Papademos. ”What we have to do now it to concentrate on implementation — less politics and more commitment. It’s not just a sprint; it’s a marathon.”

The comment underscores the mounting pressure on Samaras, whose party is a member of Greece’s unity government and who has balked at the demand for a written endorsement of the budget cuts. He also says that he has told the officials from the EU, the International Monetary Fund and the European Central Bank that he has already taken five actions that show his full committee to the austerity program, state-run Athens New Agency said on Nov. 19.

Greece really needs a sixth disbursement of loans under last year’s 110 billion-euro ($148 billion) rescue and a planned second package of 130 billion euros to avoid economic collapse. The euro area and the IMF, which are funding the two package including the next payment of 8 billion euros, want Greece’s main political leaders including the next payment of 8 billion euros, are wanting Greece’s main political leaders including Samaras to commit to spending cuts beyond the life of the Papademos-led unity government.

Papademos, who is a former ECB vice president who took over when George Papandreou’s government collapsed on November 10, will meet with Luxembourg Prime Minister Jean-Claude Juncker today before traveling over to Frankfurt to meet with ECB President Mario Draghi.

EU President Herman Van Rompuy called on ”all Greek political leaders to fully back this strategy.” After meeting with Papademos yesterday, Van Rompuy said in a statement that the euro-area finance ministers ‘’should” be in a position to authorize the next Greek loan installment at a meeting that is scheduled for Nov. 29.

”The situation is very demanding,” said Van Rompuy. ”A lot of efforts have already been done by the Greek people. However, more needs to be done to restore stability, confidence and growth.”

Barroso said that Greece faces ”exceptional” difficulties that don’t allow for ”political games” by Greek party leaders. He also said that the aim is to ensure that Greece stays in the 17-nation euro area.

George Karatzaferis, who is the head of the Laos party that is the third partner in the unity government, said he was struggling too with the demand for a written pledge on austerity and was considering addressing an open letter in his faction’s official newspaper.

”I ran into a wall on this issue,” said Karatzaferis in an interview on Mega TV yesterday when they asked him if he found any flexibility on the issue when he met EU, ECB and IMF officials in Athens recently. ”I believe they have no trust in us at all.”