JERUSALEM, March 24 (Reuters) - Israel's Defence

Ministry said on Monday it signed a contract worth hundreds of

millions of dollars with Lockheed Martin ( LMT ) unit Sikorsky

to integrate Israeli systems into 12 CH-53K Pere helicopters

that are currently under construction.

The modifications, which are required by the Israeli Air

Force, are part of a Foreign Military Sales (FMS) deal signed

between Israel and the United States several years ago, but only

made public on Monday.

The ministry said that assembly of the 12 helicopters is

currently underway at Sikorsky's headquarters in Stratford,

Connecticut. Sikorsky is building a separate production line to

modify each aircraft from the standard U.S. Marine Corps

configuration to the operational mission requirements specified

by the Israeli Air Force.

The Pere helicopters will replace Israel's Yas'ur

helicopters.