President Ricardo Martinelli warned Venezuela Friday that its decision to break off relations with Panama should not be used as an excuse to renege on its more than $1 billion debt."I don't want to think that this is an excuse not to pay and that the Venezuelan state is a deadbeat," he told reporters.Venezuela on Thursday ordered the expulsion of Panama's ambassador and three other diplomats.At least 20 people have been killed in more than a month of anti-government protests in Venezuela that President Nicolas Maduro blames on a US-backed "fascist" plot.Maduro lashed out Wednesday at Panama, calling it a "lackey" of the United States for seeking a meeting of the Organization of American States on the turmoil.But Martinelli suggested that Maduro's real motive was to get out from under huge bills owed to the Colon duty-free zone and to COPA, the Panamanian airline."Venezuela would appear to be bankrupt, although it shouldn't be because it is a very rich country," said Martinelli.It "has no excuse" to not pay off its debts, he added.The manager of the Colon Free Zone, Leopoldo Benedetti, said Venezuelan importers have about $2 billion in unpaid bills.COPA, which Martinelli said is owed $480 million, issued a statement saying its flights between Panama and Venezuela were operating normally.