SOFIA, Bulgaria (AP) — Bulgaria’s government has approved the purchase of U.S.-made Stryker combat vehicles to modernize the country’s land forces and bring them in line with NATO standards.

The decision, announced Friday by the government’s press office, followed the approval by the U.S. State Department of the sale of 183 Stryker vehicles and related gear to Bulgaria for an estimated cost of $1.5 billion.

“The aim of the project is for Bulgaria to achieve interoperability with the NATO allies, and also to acquire and maintain capabilities for the country’s defense independently, in a joint operation and in the collective defense system, as well as to participate in allied operations outside the country’s territory,” the government statement said.

Bulgaria, which is located on NATO’s eastern flank, has intensified its military modernization by replacing its outdated Soviet-built weapons systems.

In the aftermath of Russia’s full-scale invasion of Ukraine, Bulgarian Defense Minister Todor Tagarev has pledged that his country will speed up efforts to set up a heavy mechanized brigade and other projects to guarantee security in the Black Sea region.