Panama's President Ricardo Martinelli has called on Venezuela not to use its decision to break ties with his country as an excuse not to pay back a debt that tops $1bn.

"Venezuela is, it appears, practically bankrupt and this shouldn't be because it is a rich country," Martinelli said, in a speech expressing dismay at the recent diplomatic rupture.

On Wednesday, Venezuela's President Nicolas Maduro announced that he was breaking diplomatic relations with Panama over its push for an Organization of American States-sponsored mediation in the country's crisis.

Maduro accused Panama's president of conspiring with the United States to intervene in Venezuela's affairs. During a rally on Thursday, he gave the Panamanian ambassador and three other diplomats in Venezuela 48 hours to leave the country.

Foreign Minister Elias Jaua said Venezuela had also suspended debt negotiations over $1bn owed to Panamanian exporters.

"We want to express and reiterate the astonishment caused to the government of Panama by the decision of the Venezuelan government of breaking diplomatic relations with Panama. As we have shown, we find this measure lamentable and disproportionate," said Panama's Foreign Minister Francisco Alvarez de Soto.

"We don't accept accusations of interference. We find them inadequate and not based on reality," he added.