PARIS (Reuters) - The U.S. Navy expects additional U.S. and international orders for the Boeing P-8A Poseidon maritime patrol aircraft in coming months, which should extend production by two years to late 2025, a senior U.S. Navy official told Reuters.

FILE PHOTO: A U.S. Navy Boeing P-8A Poseidon maritime patrol aircraft takes part in the Malta International Airshow at SmartCity Malta outside Kalkara, Malta, September 23, 2017. REUTERS/Darrin Zammit Lupi/File Photo

Navy Captain Tony Rossi, program manager for the P-8 and its predecessor, the P-3, said the Navy was hoping to finalize the order book for the program soon to be able to “effectively and efficiently close out the production.”

He said the program could see about 21 additional orders from the U.S. Navy on top of 117 aircraft already funded, plus roughly the same number from other countries, although he declined to name potential new buyers.

The P-8, based on Boeing’s 737-800 airframe, conducts anti-submarine warfare, anti-surface warfare and shipping interdiction, and also carries electronic support measures, torpedoes, Harpoon anti-ship missiles and other weapons.

It is already operated by the U.S. Navy, Australia and India, and has been ordered by Britain, Norway, New Zealand and South Korea.

Rossi said he was urging potential buyers to place their orders soon.

“The message is clear. The time is now to make sure that production continues to get those orders filled,” he said. “I’m upbeat. I think there’ll likely be additional U.S. orders and additional FMS (foreign military sales) quantities in the next six to nine months.”

Richard Aboulafia, vice president of analysis for the Virginia-based Teal Group, said other potential buyers included Singapore and Canada. The transatlantic NATO alliance was also considering ordering the aircraft, according to sources familiar with the program.

“The market is somewhat thinner than expected, but they’ll get more orders. The production line will probably wind up running into the late 2020s,” Aboulafia said.

Boeing builds about 1.5 P-8 aircraft a month, but could slow production to extend the line, which is now slated to end in mid- to late-2023, and allow additional international customers to join the program, Rossi said.

He said demand for broad-area maritime patrol was rising given sharp increases in Russian submarine activity, and the capabilities of those vessels.