In 2014, Poland requested US Congressional approval for the purchase of the AGM-158 JASSM to extend the deep penetration strike capabilities of their F-16 Block 52+ fighters. Congress approved the sale in early October, and negotiations concluded in early November 2014. Poland signed a $250 million contract to upgrade its F-16s and equip the jets with (AGM-158) JASSM advanced cruise missiles in a ceremony at Poznan AB, Poland, on 11 December 2014. The missiles are expected to enter operational service in 2017, and Poland is contemplating an additional purchase for the long-range JASSM-ER version. In December 2015 the production contract for Lot 13 was signed. The contract includes 140 JASSMs for Finland, Poland and the US, 140 JASSM-ER missiles for the US, and data, tooling and test equipment. It is said to be the last production lot that will include non-ER versions. Poland's first modified F-16s should be ready by 2017, when the first missiles are delivered. The work is scheduled to be complete by June 29, 2019. In November 2016 The U.S. State Department approved the possible sale of 70 AGM-158B JASSM-ER to Poland.