The United States will adhere to its "expedited timeline" to deliver the Patriot aid and missile defense system to Ukraine, US Defense Department spokesperson Pat Ryder said Tuesday.

"I'm not going to get into delivery timelines, other than to say that we're confident that we'll be able to get the Patriots there on an expedited timeline," Ryder told a press briefing.

The statements coming from the United States are in light of reports suggesting that the Pentagon wanted to refurbish existing M1A1 Abrams main battle tank hulls instead of going through the process of building new tanks in a bid to get them to Ukraine faster.

Furthermore, there are currently 65 Ukrainian soldiers undergoing training on how to operate the Patriot system at the Fort Sill base in Oklahoma, the United States. They are expected to continue preparations for operating the system in Europe once they finish training in the United States.

In January, Russian Ambassador to the US Anatoly Antonov said the Pentagon's decision to train Ukrainian personnel to operate and maintain Patriot missile defense systems at the US Army post in Fort Sill, Oklahoma, is proof of Washington’s involvement in the war in Ukraine.

US President Joe Biden had said in December that he intended to supply Ukraine with patriot missile systems, underlining that "We are going to continue to strengthen Ukraine's ability to defend itself, particularly air defense. That's why we're gonna be providing Ukraine with a Patriot missile battery and training Ukrainian forces to use it."

Biden's words came in light of a visit by Ukrainian President Volodymyr Zelensky to Washington, DC. The United States involved itself excessively in security arrangements to bring Zelensky to the US, according to the White House.

However, US National Security Council Strategic Communications Coordinator John Kirby said earlier in March that Patriot systems sent to Ukraine won't be a match in efficiency in the face of Russian cruise missiles and drones.   

"The Patriot missile system is really designed to go after ballistic missiles. It is not as effective on cruise missiles, and it certainly cannot be effective against drones," Kirby stated to CNN, adding that possibilities to fend off hypersonic missiles are "limited."  

Kirby described fighting hypersonic missiles as "very, very difficult" but also did not hesitate to add that it would not "surprise" him if "Ukrainian air defenses are limited in their ability to go after hypersonic missiles." 

Read more: Russia: US Patriot systems in Ukraine would be legitimate targets

M1A1 Abrams tanks instead of M1A2 Abrams

Furthermore, Ryder said his country would provide Ukraine with the M1A1 variant of the Abrams tank instead of the M1A2 variant as initially planned in order to expedite delivery of the platform to this fall.

“After further study and analysis… the Defense Department, in close coordination with Ukraine, has made the decision to provide the M1A1 variant of the Abrams tank, which will enable us to significantly expedite delivery timelines and deliver this important capability to Ukraine by the fall of this year,” Ryder said during a press briefing.

Ryder explained that the M1A2 variant would have taken more than a year to deliver.

The US will ensure that Ukrainian troops receive training on the tanks in time for their delivery, Ryder added.

It was reported in January that the US would supply the more modern M1A2 type of Abrams tanks to Ukraine, confirming earlier rumors from US media.

President Biden announced that the US would send 31 Abrams tanks to Ukraine. However, US officials have stated that it will take a few months to finalize the training and delivery process before they can be mobilized on the battlefields in Ukraine, most likely they wouldn't be delivered before the anticipated Ukrainian counteroffensive. 

Federal regulations prevent the advanced Abrams tanks, known as the M1A2 model, from being equipped with a covert armor that uses depleted uranium, according to the report.

The M1A2 Abrams tank has upgraded targeting optics on top of the M1A1 version incorporating a separate thermal optics system that enables the tank's commander to search for targets in all kinds of weather and battlefield circumstances.

It was said at the time that the tanks will take months to be delivered to Ukraine, noting that the step aims to provide Ukraine with long-term defense.

The location upon which Ukrainian servicemen will train on operating the M1 Abrams was not yet determined.

Costing around $10 million a piece, the US-made complex battle tank is very difficult to maintain and will pose a logistical challenge to be resupplied as it operates on jet fuel.