WASHINGTON, July 15 (Reuters) - The US State Department has approved the potential sale of HIMARS rocket systems to Estonia, missiles to Norway and torpedoes to South Korea in separate deals that could be worth more than US$1.5 billion in all, the Pentagon said on Friday (Jul 15).

The sales comes as European countries increase arms purchases after Russia invaded Ukraine, heightening security fears across the region.

HIMARS systems donated by the United States and allies are being employed by Ukraine in its fight with Russia.

The package approved for Estonia would include up to six M142 High Mobility Artillery Rocket System (HIMARS) launchers, munitions, support equipment, spares and technical support, the Pentagon said.

The Pentagon's Defense Security Cooperation Agency notified Congress of the possible sale to Estonia alongside the two other foreign military sales on Friday.

The State Department's separate approvals of the potential sale of medium-range air-to-air missiles and related equipment for Norway in a deal valued at up to US$950 million, and MK 54 Lightweight Torpedoes to South Korea for an estimated value of US$130 million also were made public on Friday.

Despite approval by the State Department, the notification does not indicate that contracts have been signed or that negotiations have concluded.

The Pentagon said Lockheed Martin Corp was the prime contractor for the HIMARS systems and Raytheon Technologies was the prime contractor for the up to 205 AIM-120 C-8 or D Advanced Medium-Range Air-to-Air missiles.