Obama discusses Greek debt crisis with Merkel, Tsipras

U.S. President Barack Obama spoke on Tuesday morning with German Chancellor Angela Merkel and Greek Prime Minister Alexis Tsipras by phone, urging all sides to reach an agreement that allows Greece to stay in the eurozone.

The U.S. and German leaders agreed that "it is in everyone's interest to reach a durable agreement that will allow Greece to resume reforms, return to growth, and achieve debt sustainability within the eurozone", the White House said in a statement.

The leaders also noted that their economic teams are monitoring the situation in Greece and remain in close contact, after Greeks voted "no" to creditors' bailout offer in a referendum on Sunday.

Obama reiterated that Greece and its creditors should "reach a mutually-acceptable agreement" in a phone call with Tsipras, the White House said in a separate statement.

The calls came just before an emergency eurozone summit in Brussels to seek a solution to the Greek debt crisis. Eurogroup President Jeroen Dijsselbloem said Tuesday that Greek proposals needed to be "credible" to seek a way out.

Since July 1 Greece has already been in arrears to the International Monetary Fund and the country needs to repay 3.5 billion euros (3.8 billion U.S. dollars) in loan installments to the European Central Bank on July 20. Without emergency assistance, Greece seems to be heading to default.