WASHINGTON, July 19 (Reuters) - The United States on Wednesday (Jul 19) announced additional security assistance of about US$1.3 billion for Ukraine in its war with Russia, the package including air defence capabilities, drones and munitions.

"This announcement represents the beginning of a contracting process to provide additional priority capabilities to Ukraine," the Pentagon said in a statement.

The United States is using funds in its Ukraine Security Assistance Initiative (USAI) program, which allow President Joe Biden's administration to buy weapons from industry rather than pull from US weapons stocks.

The package includes four National Advanced Surface-to-Air Missile Systems (NASAMS) and munitions; 152 millimetre artillery rounds; mine clearing equipment; and drones, according to the Pentagon.

The US Department of Defense announced the aid a day after a virtual meeting of the Ukraine Defense Contact Group, allies assisting Ukraine as its forces press a counteroffensive against Russian troops occupying Ukrainian territory.

Delivery of the weapons and systems depends on their availability and production timeline.

The Pentagon has provided more than US$10.8 billion in security assistance for Ukraine under the USAI in fiscal 2023, in seven separate tranches. The planned package would be the eighth. In the fiscal year that ended Sep 30, 2022, Washington put US$6.3 billion worth of USAI funds to work buying for Ukraine's defense.

Overall, the U.S. has sent over US$40 billion in the form of security and military assistance to Ukraine since Russia invaded in February 2022.

The package includes two different types of loitering munitions, the Phoenix Ghost drone made by AVEVEX, a private company in California, and the Switchblade, made by AeroVironment.

Earlier this month, the United States announced that it will send Ukraine cluster munitions - prohibited by more than 100 countries - to Ukraine. Human rights groups and some US allies, including Germany and Canada, oppose that decision.