Slovakia wants the helicopters to replace its fleet of 14 Soviet-designed Mil Mi-17 copters, which are produced and maintained by the Russian-owned firm Rostec.

The Foreign Military Sales agreement now requires congressional approval, and then negotiations will begin in earnest between the two governments.

When the plan to acquire the helicopters was announced by Slovakia's government, the estimated cost was $348 million. The DSCA announcement pegs the estimated cost at $450 million. Whether that price increase will prove a roadblock to an eventual deal is unclear; Slovakia's 2014 military budget was a relatively small €744 million (US $848 million), euros, so the price jump is not negligible.

Slovakia is but the first of what UH-60 producer Sikorsky hopes is a series of countries in Eastern Europe turning toward the US to meet their helicopter requirements.

Samir Mehta, president of Sikorsky military systems, told reporters Feb. 5 that he is seeing significantly more interest from the region since Russia's invasion of Ukraine a year ago.

"I don't think there's any secret, geopolitically, what's causing that demand," Mehta said. "A lot of these countries have Russian equipment they have traditionally used, and now they want to be able to pivot over to using Western equipment and what the DoD uses. And that means a lot of interest, specifically in the Black Hawk, so we're seeing a huge spike up in interest from those countries."

In addition to the helicopters themselves, the deal will include "twenty T700-GE-701D Engines (18 installed and 2 spares); twenty Embedded Global Positioning Systems/Inertial Navigation Systems; two Aviation Mission Planning Systems; one Aviation Ground Power Unit; eleven AN/APX-123 Identification Friend or Foe Transponders; twenty Very High Frequency (VHF)/Digitally Selective Calling AN/ARC-231 radios; eleven ARN-147 VHF Omni Ranging/Instrument Landing System (VOR/ILS); eleven AN/ARN-153 Tactical Air Navigation Systems; and eleven AN/ARC-201D Single Channel Ground and Airborne Radio Systems radios," according to the DSCA notice.

Twitter: @AaronMehta