Poland's defense minister praised long-range missiles the country is buying from the U.S. as the most modern military equipment Poland has ever had and said that they are especially needed at this time of tension in the region.

A NATO member, Poland for years has worked to modernize a military once based on Soviet-built equipment. Those efforts intensified after Russia annexed Crimea earlier this year and gave support to the pro-Russian rebels in eastern Ukraine, actions that have made Warsaw nervous.

"Never in history have we had such modern weapons as we are getting as a result of this deal," Defense Minister Tomasz Siemoniak said Thursday at a ceremony for the $250 million deal. The deal, already signed in the U.S., was signed by a Polish general Thursday.

The ceremony took place in a hangar with F-16s and a model of the missile at the Krzesiny air base in the city of Poznan. The deal includes the purchase from U.S. aerospace and defense contractor Lockheed Martin Corp. of 40 joint air-to-surface missiles, which will be integrated into the Polish air force's fleet of F-16 fighter jets.

Siemoniak added that now, with the Russian-Ukrainian conflict, such modern weaponry "is especially needed."

Both he and the U.S. Ambassador to Poland, Steven Mull, hailed the deal as a sign of the strength of the U.S.-Polish alliance.

The deal for the 40 AGM-158 JASSM-type missiles also includes associated equipment, training and logistical support needed to make them operational.

Delivery is to take place in 2015 and 2016, and the missiles are scheduled to be operational in 2017.

Both the U.S. State Department and Congress approved the deal this fall, making Poland the third country allowed to buy the missiles after Australia and Finland.