WARSAW, Poland (AP) — Poland has received its first shipment of U.S.-made HIMARS rocket launchers as part of a defense upgrade amid security concerns due to the war in neighboring Ukraine.

Defense Minister Mariusz Blaszczak and military officials attended an acquisition ceremony at a Warsaw air base on Monday.

Blaszczak said that combat in Ukraine had proven the value of the HIMARS and that NATO member Poland was seeking to procure additional launchers, with a goal of acquiring some 500 units.

“We are watching the developments in Ukraine, and we know that artillery has a key role in the war, in repelling the Russian invasion," he said.

Under a 2019 contract, Poland is spending some $414 million (380 million euros) to buy 18 advanced combat HIMARS launchers and two HIMARS training launchers, with ammunition and related equipment. The deal includes logistics and training.

The launchers will go to the 1st Artillery Brigade in northeastern Poland, Blaszczak said.

“Their task will be to deter (an) aggressor and strengthen Poland's armed forces on the nation's and NATO eastern flank,” the minister said.

A HIMARS academy is to be launched in the city of Torun to provide logistics, servicing and training, including for troops from other NATO countries that have or plan to get the launchers.

Produced by American aerospace company Lockheed Martin, the High Mobility Artillery Rocket System is a multiple rocket launcher with a range of up to some 300 kilometers (190 miles) developed in the late 1990s for the U.S. armed forces.

Poland is buying billions of dollars’ worth of weapons, chiefly from the U.S. and South Korea, including fighter jets, to modernize its armed forces.

Some of the equipment will replace weapons - including over a dozen Soviet-made MiG-29 jet fighters - that Poland agreed to give Ukraine for its defense against Russia.

Poland's right-wing government, which will be seeking a third term in a fall parliamentary election, is giving the purchases wide publicity, seeking to reassure Poles amid a military conflict across their eastern border.

Last year, Poland received a number of U.S. Patriot missile systems, and deliveries of another battery are expected this year. The first deliveries of Abrams tanks have also arrived from the U.S., as well as deliveries of tanks and howitzers from South Korea.