NICOSIA, May 21 (Reuters) - U.S. Vice President Joe Biden visited ethnically-split Cyprus on Wednesday to lend support to complex peace talks on an island which has the potential to play an important role in easing Europe's reliance on Russian gas.
Biden, on a two-day visit, was due to meet Cypriot President and Greek Cypriot leader Nicos Anastasiades and Turkish Cypriot leader Dervis Eroglu.
Cyprus has been split since a 1974 Turkish military invasion, dividing the north from the south after a brief Greek Cypriot coup engineered by the military then ruling Greece.
"It's long past time ... that Cypriots are reunited," Biden said on his arrival.
A settlement to the Cyprus dispute, one of the oldest on the United Nations agenda, has eluded an army of mediators over the years.
Attempts to seal a deal have gained urgency since the discovery of vast quantities of natural gas in the eastern Mediterranean between Cyprus and Israel.
"The discovery of hydrocarbons in the Cypriot (waters) could position Cyprus, we believe, as an energy and economic leader in the region," a senior U.S. administration official said before the visit.
Cyprus has licenced a U.S. company, Noble, to drill for natural gas after discoveries off its southern coast. It has also licenced European companies ENI and Total to search for gas.
U.S. support for further European Union sanctions on Russia over the annexation of Crimea would also feature prominently in talks, sources said.
Cyprus, a key business partner of Russia in the EU, opposes further sanctions which could hurt its economy, still struggling after being bailed out by the International Monetary Fund and the EU last year.
Biden, who is the most senior U.S. official to visit Cyprus since Lyndon Johnson in 1962, was due to meet religious leaders from both sides of the divide on Thursday, have separate talks with the leaders of the Greek and Turkish Cypriots and attend a joint dinner with the two.
Cypriot sources said it was unlikely that Biden would announce any breakthrough in confidence-building measures under discussion between the two sides for months. "It will be more like a wish-list," one Cypriot source said.
A new round of reunification talks was launched between Anastasiades and Eroglu on Feb. 11. Mediators are trying to unite the island as a two-zone federation, but fundamental differences remain on issues such as power sharing and the property rights of thousands displaced in past conflict. (Reporting by Michele Kambas; Editing by Ruth Pitchford)