The British and Norwegian governments are moving forward contractually in their acquisition of Lockheed Martin F-35 Lightning II fighter aircraft.

Britain's Ministry of Defense says it has signed a contract for the first production batch of four Lightning II aircraft for the Royal Navy and Royal Air Force, while Norway has signed an agreement with Lockheed Martin for two aircraft from the company's eighth F-35 production lot.

"The contract for the F-35B aircraft forms part of the MOD's investment in Lightning II over the next 5 years to procure an initial 14 of these multi-role fifth generation aircraft, as well as putting in place the necessary support arrangements and infrastructure," Britain said.

The "B" model F-35 is the aircraft's vertical takeoff and landing variant.

The contract signed does not cover the aircraft's power plant. Contracts for engine will be awarded at a later date, the ministry said.

Britain plans 14 A and B F-35 aircraft for delivery over the next five years.

"Looking to the future, the investment we are making in the F-35 aircraft will ensure we are securing the skies for decades to come, providing the UK with the latest stealth technology and multi-role aircraft capability," Minister for Defense Equipment Support and Technology Philip Dunne said. "Not only does our investment in these next generation aircraft afford us air superiority, but the UK's Tier-One status in the entire (F-35) program provides UK industry with a unique opportunity to produce world-leading products, technologies and manufacturing expertise for coming decades.

"The aircraft will be a powerful testament to the strength and capability of British industry."

Announcement of the contract coincided with a British test team in the United States completing initial aircraft handling trials for ASRAAM and Paveway IV weapon systems on the F-35B variant at a U.S. Navy facility.

The trials, the ministry said, were an "important step" in integrating weapons onto the F-35B and allow test pilots to understand how the weapon systems affect aircraft performance and handling.

The announcement also coincided with Lockheed Martin UK opening a visualization center in Britain for pilots and engineers of F-35 aircraft to test and evaluate software designed for the fighter.

Meanwhile, Norway's Ministry of Defense reports it has signed a contract with Lockheed Martin for two of the 43 F-35s the company is building in its eighth production lot.

The two aircraft ordered will bring to four the number of F-35s to be delivered next year and in 2016 for training of its pilots at a base in the United States.

The contract is for the aircraft airframes. Lockheed will be responsible for 100 percent of any cost overruns in their production, as well as half of the cost of modifications found to be necessary during the test program.

"This agreement is another example of the value of this partnership for Norway," said Maj. Gen. Morten Klever, program director of the Norwegian Fighter Aircraft program. "We are now flying under the same conditions as all the other partners, including the Americans themselves, and we can claim that the industry covers overruns.

"This reduces the risk to Norway, and makes it easier for us to plan further work."

The ministry said negotiations on the contract that will cover the next production batch of aircraft are already underway. That contract will cover six aircraft for Norway, which plans to eventually acquire 52 of the jets.

The U.S. military recently gave Lockheed Martin a $4.1 billion award for Lot 8 aircraft.