"Indeed, the recent talks between Raytheon (and Poland) are very, very promising and one may say that a breakthrough has taken place," Macierewicz told Reuters.

"Raytheon has agreed to our minimal condition aimed at securing that at least 50 percent of the money which is to be spent of the Patriot system (Raytheon's missile defense system) would be spent on works done by Polish plants," he said.

The missile defense tender, whose value defense officials estimate at around $5 billion, is central to Warsaw's large-scale army modernization program, speeded up in response to the Ukraine crisis and Russia's renewed assertiveness in the region.

(Reporting by Wiktor Szary; Writing by Marcin Goettig)