WASHINGTON - The US State Department has approved the possible sale of up to 600 Patriot air defense missiles to NATO ally Germany for an estimated cost of $5 billion, the Pentagon said on Thursday.

"The proposed sale will improve Germany’s capability to meet current and future threats and increase the defensive capabilities of its military," the Pentagon's Defense Security Cooperation Agency said in a statement.

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Under new NATO defense plans, Germany will need to quadruple its air defenses to protect infrastructure and military forces in the event of severe tensions or a war, one security source told Reuters last month.

Germany had 36 Patriot air defense units, which launch missiles, when it was NATO's frontline state during the Cold War. Today, German forces are down to nine Patriot units, after donating three to Ukraine since the Russian special military operation in 2022.

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The prime contractor for the possible sale, which includes related equipment and technical assistance, will be Lockheed Martin, the Pentagon agency said.

The agency notified Congress of the possible sale on Thursday.