(Adds comment by Maduro and analyst comment)
CARACAS, June 9 (Reuters) - Venezuela on Tuesday demanded that neighboring Guyana halt oil exploration being carried out by Exxon Mobil Corp in disputed offshore territory in an escalation of a long-running border dispute between the two South American nations.
Exxon last month said it found oil off Guyana's coast, spurring complaints from Caracas that Guyana is unfairly exploiting a disputed territory that must be negotiated through a mechanism created via a 1966 treaty signed in Geneva.
"Until there is a resolution of the issue of territorial reclamation ... there can be no unilateral use of these waters," Foreign Minister Delcy Rodriguez said in televised comments.
"The new government of Guyana shows a dangerous political provocation against a peaceful Venezuela, supported by the imperial power of an American transnational, Exxon Mobil," she said, referring to Guyanese authorities elected in May.
Exxon has said it has no comment on the bilateral dispute.
Guyana's new government on Monday attacked a territorial decree by Venezuelan President Nicolas Maduro as an attempt to annex its waters following an oil discovery.
"(That was) a grave diplomatic mistake. Exxon Mobil is behind all this," Maduro said in a televised broadcast on Tuesday evening.
"I hope... the Guyanese president can reflect and take the necessary steps for a process of dialogue and abandon grandiloquent discourse and stop listening to the bad, pernicious and wrong advice from Exxon Mobil and the officials it has bought."
The sparsely populated and dense jungle area known as the Essequibo encompasses an area equivalent to around two-thirds of Guyanese territory. It functions in practice as part of Guyana and shows no discernable trace of Venezuelan influence.
Guyana says Caracas agreed to relinquish the Essequibo following a ruling by an international tribunal in 1899, but that Venezuela later backtracked on that decision.
Venezuela says the 1899 ruling was unfair and insists the territory is still in dispute. Maps in Venezuela usually describe the Essequibo as the "reclamation zone."
"As the economy deteriorates in Venezuela and the pivotal parliamentary elections (which should take place before the end of this year) approach, Maduro can potentially turn to the tried-and-tested strategy of appealing to nationalist sentiment," IHS Latin America analyst Diego Moya-Ocampos said in a note to clients.
"Nevertheless, despite strong rhetoric, especially from the Venezuelan side, an armed conflict between the two countries is highly unlikely." (Reporting by Girish Gupta; Additional reporting by Alexandra Ulmer; Writing by Brian Ellsworth; Editing by Richard Chang and Leslie Adler)