WASHINGTON: The United States on Wednesday announced the approval of a $7.3 billion sale of upgrades for Poland’s F-16 warplanes, boosting the defenses of a NATO member that shares a lengthy border with war-torn Ukraine. “This proposed sale will support the foreign policy goals and national security of the United States by improving the security of a NATO ally that is a force for political and economic stability in Europe,” the Defense Security Cooperation Agency (DSCA) said in a statement. “The F-16 Viper Midlife Upgrade (MLU) will bolster Poland’s air defense and surveillance capabilities, support national security, and strengthen Poland’s defense and contributions to NATO,” it said. The State Department approved the possible sale and the DSCA on Wednesday provided the required notification to Congress, which still needs to sign off on the transaction.