The United States said Friday it had approved the sale of $1.5 billion in armored vehicles to Bulgaria, its latest major deal with an eastern NATO ally as war rages in Ukraine.

The State Department informed Congress of its green light to Bulgaria's request to buy 183 Stryker vehicles, more than half of them infantry carrier vehicles.

"The proposed sale will improve Bulgaria's rapid infantry deployment and force projection capability. Bulgaria will use this enhanced capability to strengthen its homeland defense and deter regional threats," it said in a statement.

The sale comes a month after Bulgaria, which has large stocks of Soviet weaponry, agreed to send around 100 armored personnel carriers to Ukraine.

It marked the first major transfer of military aid to Ukraine from Bulgaria, which has historic ties to Russia and has seen divisions over support to Ukraine.

The United States has been ramping up military aid and sales to Ukraine and NATO allies since Russia's invasion last year.

To Poland, one of the most stalwart supporters of Ukraine, the United States recently approved $12 billion in Apache attack helicopters and earlier agreed to sell advanced Abrams tanks.