WASHINGTON (AP) — The U.S. is sending an additional $275 million in military aid to Ukraine, including large amounts of ammunition and high-tech systems that can be used to detect and counter drones in its ongoing war with Russia, according to U.S. officials.its ongoing war with Russia, according to U.S. officials.

The total aid amount is smaller than most of the recent packages the U.S. has delivered, and it comes as many military officials and experts predict a reduction in attacks during the winter. NATO Secretary-General Jens Stoltenberg said Russia appears to be slowing its military activities to regroup and launch a new offensive when the weather warms.

The officials said the latest package of aid includes 80,000 rounds of ammunition for howitzers and an undisclosed amount of ammunition for the High Mobility Artillery Rocket System, known as HIMARS. It also includes systems to counter drones and air defenses, along with more HUMVEES, generators and other combat equipment. The officials spoke on condition of anonymity to discuss the aid package prior to its public release, which is expected Friday.

Drone attacks by both sides have been increasing, making detection of the unmanned explosives critical for Ukrainian forces. Russia bought hundreds of attack drones from Iran over the summer, and officials said this week that Moscow is looking to do more of the same.

Russian forces have increasingly targeted Ukraine's civilian infrastructure including power plants, leaving thousands without heat and electricity as the winter months set in.

In addition, several recent drone attacks struck two strategic Russian air bases more than 500 kilometers (300 miles) from the Ukraine border early this week. Moscow blamed Ukraine, which didn't claim responsibility.

Including the latest aid, the U.S. has now committed more than $19.3 billion in weapons and other equipment to Ukraine since Russia attacked on Feb. 24. The aid will be provided through presidential drawdown authority, which allows the Pentagon to take weapons from its own stocks and quickly ship them to Ukraine.