CARACAS, Venezuela (Reuters) -- Venezuela on Sunday revived a
                  century-old border dispute with Guyana over a mineral-rich area the size of
                  Florida, probably the last major territorial dispute in the Americas.

                  Venezuela claims almost two-thirds of Guyana, an English-speaking enclave
                  on the northeastern shoulder of South America. The dispute revolves around
                  the Essequibo region, a 61,000-square mile (158,000-square km)
                  unpopulated area thought to be rich in minerals, including gold and
                  diamonds.

                  Britain, then the colonial power over British Guiana, and Venezuela argued
                  over the boundary for much of the 19th century before accepting the
                  decision of an international Tribunal of Arbitration in 1899.

                  The dispute resurfaced half a century later following the death of Venezuela's
                  lawyer at the talks. He said in a letter opened posthumously that the
                  settlement was void because it was the result of a secret deal. The dispute
                  has simmered since then, with the United Nations eventually becoming
                  involved.

                  The Venezuelan Foreign Ministry said on Sunday it considered the "painful"
                  act signed exactly 100 years ago, on Oct. 3, 1899, in Paris, to be "null and
                  an irritant." The ministry said in a statement that the agreement "illegally
                  stripped our country of Essequibo."

                  The ministry added it would continue to seek with Guyana "satisfactory
                  solutions" to the "controversy" under the auspices of the United Nations,
                  which in 1989 named a mediator in the dispute.

                  Some Caracas-based diplomats have said the Essequibo issue was bound to
                  assume a larger significance after Venezuelan President Hugo Chavez, an
                  outspoken nationalist, took office eight months ago.

                  "We have started to take some actions in the past few months in order to
                  bring the issue to the negotiating table," Chavez told reporters on Saturday.
                  He did not elaborate.

                  Guyana's ambassador to Venezuela, Bayney Karran, said he doubted
                  Chavez would up the ante on Essequibo.

                  The diplomat recalled to Reuters recently that Chavez said shortly after
                  taking power that Venezuela's border disputes -- there is another, minor one
                  with Colombia -- would probably not find a lasting solution during his term
                  of office.

                  Usually seldom mentioned in Venezuela, the Essequibo dispute was widely
                  covered by the press over the weekend.

                  Major newspapers dedicated long articles, complete with historical data and
                  maps, referring to the 1899 decision as "a major theft" that left "a gaping
                  wound."

                  The dispute, with roots in the colonial history of the only part of South
                  America settled by the Dutch, British and French, is by many accounts a
                  bizarre one.

                  The Venezuelan claim is largely based on a posthumous letter opened 50
                  years ago. The document was a memorandum written in 1944 by a U.S.
                  lawyer, Severo Mallet-Prevost, who had represented Venezuela before the
                  Paris tribunal.

                  Mallet-Prevost had asked the letter to be opened only after his death. The
                  letter asserted the 1899 settlement was null and void because it was the
                  result of a behind-the-scenes deal. But all the other participants in the
                  tribunal had died and no balancing view was available.

                  Venezuela formally raised the invalidity of the 1899 accord at the U.N. in
                  1962, four years before Guyana won independence from Britain.