According to CNN, citing a source familiar with the news, the US is anticipated to announce the acquisition of a sophisticated, medium to long-range surface-to-air missile defense system for Ukraine this week.

Other military aid to Kiev, which Washington is expected to reveal this week, includes more artillery ammunition and counter-battery radars, according to the source.

Read more: Russia vows immediate response if Kiev attacks with long-range missiles

The source revealed that Ukrainian officials have sought the US for the NASAMS medium to long-range surface-to-air missile defense system, and if furnished with NASAMS, Ukrainian forces will require training.

According to CNN, which cited US sources, the US does not anticipate the military equipment it has provided to Ukraine, particularly the High Mobility Artillery Rocket System (HIMARS), to affect the situation on the ground quickly.

Read more: Ukrainian MoD: HIMARS arrive in Ukraine

Earlier this month, US President Joe Biden announced that he had informed Ukraine's Volodymyr Zelensky that Washington will supply Kiev with an additional $1 billion in additional aid.

On June 23, the White House announced that the United States is sending a new batch of military supplies to Ukraine. The new batch of arms supply is worth $450 million of shipments that include more rocket systems for Ukraine to use against the Russian forces. 

"This package contains weapons and equipment, including new High Mobility Artillery Rocket systems," said White House spokesperson, John Kirby. Included in the supplies are thousands of rounds of artillery ammunition and patrol boats.

On the same day, Ukraine announced receiving a batch of HIMARS, weapons set on top of the Ukrainian wishlist, and the Ukrainian Minister of Defense Oleksiy Reznikov thanked, via his Twitter account, his “colleague and friend Secretary of Defense Lloyd J. Austin III for these powerful tools!"

With the latest shipments, the US contribution to Ukraine's military will amount so far to $6.1 billion, Kirby said.

According to the Defense Department, the new package includes guided multiple launch rocket system bombs, 18 howitzers, 36,000 rounds of artillery ammunition, and two more Harpoon anti-ship missile systems.

The package also includes $650 million in Ukraine security assistance initiative money, as well as two more Harpoon coastal defense systems and hundreds of secure radio, night vision, and thermal weapon sites, according to the Defense Department.

The Biden administration unveiled a military aid package for Ukraine in early June that included 1,000 anti-tank Javelin missiles, 50 command launch units, four Mi-17 helicopters, and four HIMARS.