Israel Aerospace Industries won a contract to supply the navy with three Super Dvora-class Mark III fast patrol craft to bolster maritime security.

The main function is to protect offshore natural gas fields from seaborne attack at a time when Beirut reportedly plans to award oil and gas exploration contracts to international companies in disputed waters bordering Lebanon.

Neither the navy nor state-owned IAI, flagship of Israel's defense industry, put a value on the contract, but the Globes business daily cited sources as saying it would run to "tens of millions" of dollars.

The new 90-foot craft will increase the navy's fleet of fast attack ships to 13, including six delivered under a 2004 contract and four others under a 2006 contract.

The navy also operates five Shaldag Mark III fast patrol craft built by the privately owned Israel Shipyards of Haifa, the navy's main base on the eastern Mediterranean, for coastal protection.

The Dvora-class vessels are built by IAI's Ramta Division at Beersheva in southern Israel. The Mark III boats built in 2004 are deployed primarily in Israel's southern waters off the Palestinian-ruled Gaza Strip.

The fast and agile Mark III craft are designed to operate in shallow waters for missions like landing commandos of the navy's elite Flotilla 13 unit,

They have a maximum full-load displacement of 72 tons, a top speed of 50 knots and are powered by two U.S.-produced Detroit Diesel 12V-400 M90 engines developed by Germany's MTU Aero Engines.

They have an operational range of 700 nautical miles and are armed with 25-30mm Typhoon cannon built by state-owned Rafael Advanced Defense Systems.

Israel's dispute with northern neighbor Lebanon over their maritime exclusive economic zones centers of a 328-square-mile triangle of water. Israel claims it is part of its Leviathan field, the largest of the offshore gas fields it has found since 2009.

The Lebanese claim those waters and suspect the Israelis plan to siphon off gas from a northern extension of that gas-bearing strata.

The dispute is now before the United Nations, and Lebanon is seeking to redraw its border with Israel.

The land boundary remains disputed and for years there have been clashes between Israeli forces and Lebanon's Iranian-backed Hezbollah movement, which fought a 34-day war with Israel in 2006.

Hezbollah, heavily armed with Iranian and Syrian missiles capable of hitting Israeli offshore facilities, has vowed it will strike Israel if it violates waters claimed by Beirut.

Globes quoted Israeli officials as saying Lebanon is about to award offshore drilling licenses to international companies bidding for exploration blocks in Lebanese waters that run north to the Syrian border.

Even without the Israeli navy's buildup, with the first of the new Dvora Mark III craft scheduled for delivery within a year, it outnumbers and outguns Lebanon's handful of coastal patrol craft.

The Israeli force is also scheduled to get more firepower with Saar-class missile boats upgraded to "mini-corvette" class to expand maritime control and sovereignty far from territorial waters.

The initial batch of the current Saar 4 and 4.5-class vessels entered service 35 years ago. The new Saar S-72, armed with IAI's Barak air-defense missiles, was unveiled by Israel Shipyards earlier this year.