Greek conservative leader yet to sign austerity pledge: source
"So far Samaras has not given a letter of commitment and this is a problem," the source told Reuters on condition of anonymity.
His New Democracy party declined comment.
A separate source at the PASOK socialist party said its leader, George Papandreou, had already provided a signed undertaking to support the measures passed by parliament early on Monday.
(Reporting by Renee Maltezou; editing by David Stamp)