WASHINGTON, July 30 (Reuters) - The U.S. State Department said on Friday it has approved the potential sale of 18 CH-53K heavy lift helicopters to Israel in a deal valued at up to $3.4 billion. The package would include engines, navigation systems, weaponry, support equipment, spares and technical support. Lockheed Martin Corp (LMT.N)and General Electric Co (GE.N)are the prime contractors on the deal. The State Department said in a statement "the United States is committed to the security of Israel, and it is vital to U.S. national interests to assist Israel to develop and maintain a strong and ready self-defense capability." Despite the approval by the State Department, the notification does not indicate that a contract has been signed or that negotiations have concluded.