"We take note of the intention of the Greek authorities to hold a referendum," European Council President Herman Van Rompuy and European Commission President Jose Manuel Barroso said in a joint statement, referring to Athens' intention to hold a referendum on the Oct. 27 summit deal.

"We are convinced that this agreement is the best for Greece. We fully trust that Greece will honour the commitments undertaken in relation to the euro area and the international community."

Barroso and Van Rompuy added that they had spoken to Greek Prime Minister George Papandreou by phone and said euro zone leaders would discuss the referendum issue in more detail on the sidelines of the G20 meeting in Cannes on Nov. 3-5.