(Reuters) - Turkey said on Thursday it had scrambled military jets to intercept an Israeli plane that violated northern Cypriot airspace this week, and demanded an explanation for the incursion.

An Israeli military spokesman declined to comment on the accusation. But the incident marked a fresh source of tension between the former allies.

Relations between Turkey and Israel fell apart after Israeli commandos raided the Mavi Marmara aid vessel in May 2010 to enforce a naval blockade of the Gaza Strip and killed nine Turks in clashes with pro-Palestinian activists.

Monday´s reported air incursion coincided with tensions on the Mediterranean island of Cyprus over oil and gas exploration plans there, which could hinder U.N.-backed efforts to reunite the island.

"A plane belonging to Israel, the model of which could not be identified, violated KKTC (Turkish Republic of Northern Cyprus) airspace (above its territorial waters) five times," the Turkish military said in a statement posted on its website.

"In response to this situation, our 2XF-16 plane based at Incirlik was scrambled and our planes carried out patrol flights in KKTC airspace, preventing the said plane from continuing to violate KKTC airspace," said the statement.

Turkey´s foreign ministry said it had contacted Israel´s mission in Ankara, seeking an explanation for the incursion.

In Jerusalem, an Israeli military spokeswoman said she was checking the report.

Cyprus has been divided since 1974, when the Turkish military invaded the island after a short-lived Greek Cypriot coup engineered by the military junta then in power in Athens.

Turkey still keeps about 30,000 troops in the north and is the only nation that recognizes the self-declared Turkish Republic of Northern Cyprus.

ENERGY EXPLORATION TENSIONS

The internationally recognized Greek Cypriot government reported an offshore natural gas discovery in December but its attempt to exploit the reserves has been challenged by Turkey.

Ankara has in turn given approval for Turkey´s state-run oil firm to carry out oil and gas exploration in six offshore areas around northern Cyprus, drawing condemnation from the Greek Cypriot government, which lays claim to the territory.

Israel has separately reported two major energy finds offshore in the sea separating it from Cyprus.

Israel has worked to enhance ties with Cyprus and Greece as its relations with Turkey have frayed.

The eastern Mediterranean has recently seen joint Israeli military maneuvers with its partners, as well as long-distance training by Israel´s air force for a possible strike against Iran´s nuclear facilities.

Israel uses warplanes and pilotless drones, as well as naval craft, to patrol its offshore natural gas fields.

Turkey stirred fears of a possible confrontation at sea by saying last year it would boost its naval patrols in the eastern Mediterranean.

But a senior Israeli military officer told Reuters there had been no discernible increase in Turkish naval operations in Israel´s economic waters, which extend 187 km (117 miles) from its coast.

(Additional reporting by Dan Williams in Jerusalem and Tulay Karadeniz in Ankara; Writing by Daren Butler; Editing by Andrew Heavens) (© Thomson Reuters 2012. 05/17/12)