(ANSA-AFP) - WARSAW, JAN 30 - Poland on Friday signed contracts worth over four billion dollars for "the most modern anti-drone system in Europe" to protect its eastern border, Prime Minister Donald Tusk announced. Poland, which lies on both NATO and the EU's eastern flank, has in recent years invested heavily to modernise its military following fears of a Russian threat. "This is a historic moment ... we are truly at an absolute turning point in the effective, high-performance defence of Poland's, Europe's, and NATO's eastern border," Tusk said. He added that Poland's borders will be "the best protected in Europe". The cost "will be close" to 3.6 billion euros reported by Polish media earlier, Defence Minister Wladyslaw Kosiniak-Kamysz confirmed. The system, named "San", will include 18 anti-drone batteries, 52 firing platoons, 18 command platoons and around 700 vehicles and will be fully operational in two years, he added. The contracts signed cover Polish public and private companies as well as Norway's Kongsberg. (ANSA-AFP).