WARSAW (Reuters) - Poland may be granted U.S. government export approval to buy eight Patriot missile defence systems from Raytheon Co within the next few months, a senior Raytheon official told a Polish news agency on Friday.

NATO member Poland has sped up efforts to overhaul its military following Russia’s annexation of Ukraine’s Crimea peninsula and Moscow’s renewed military and political assertiveness in the region.

Defence Minister Antoni Macierewicz said on Friday Russian unmanned aerial vehicles (UAVs) had repeatedly violated Poland’s airspace. The Rzeczpospolita daily, citing border guard documents, said Russia has sent its drones over Poland from the Kaliningrad Region at least four times this year.

“Unfortunately, we have to say that threats associated with (Russian) drones are nothing new, it is a process that we have observed throughout the year,” PAP news agency cited Macierewicz as saying.

Poland asked Washington in September for approval to buy the systems, aiming to close a $5 billion deal that is central to a thorough modernization of its armed forces by 2023. As advanced military technology, special permission must be obtained from the U.S. government for purchase.

“Concrete decisions are expected within the next few months,” John Baird, vice president of Raytheon Poland programs, told the private Newseria Biznes agency.

Poland is also in talks with Lockhead Martin’s MEADS joint venture regarding the acquisition of Medium Extended Air Defense Systems (MEADS).