Originally Published: 21 MAR 23 12:01 ET

Updated: 21 MAR 23 15:11 ET

By Natasha Bertrand and Haley Britzky, CNN

(CNN) -- US Patriot missile defense systems and Abram tanks are set to be deployed to Ukraine faster than originally planned, US defense officials said on Tuesday.

A group of 65 Ukrainian soldiers will complete their training on the systems at Fort Sill, Oklahoma, in the coming days, the defense officials said.

The troops will then move on to Europe for additional training on the two Patriot systems -- one American and one built by the Germans and Dutch -- that will be deployed to Ukraine in the coming weeks, the officials told reporters at Fort Sill.

The announcement of the acceleration of Patriot deployments came shortly after it was reported that the US will accelerate the time it takes to ship Abrams tanks to Ukraine by sending older M1-A1 models of America's main battle tank instead of the more modern version of the tank, according to two US officials.

The decision to speed up the delivery of tanks and Patriots comes as Ukraine is preparing to launch a spring offensive against Russian forces, built largely around the more powerful and more advanced systems Western countries have agreed to send, including tanks and other armored vehicles.

US trainers at Fort Sill, where the 65 Ukrainians have been training since January 15, were able to significantly speed up the timeline of the course because of the Ukrainians' baseline knowledge of air defense systems, the officials said.

"Our assessment is that the Ukrainian soldiers are impressive, and absolutely a quick study," said Brig. Gen. Shane Morgan, the Fort Sill commander. "Due to their extensive air defense knowledge and experience in a combat zone, it was easier -- though never easy -- for them to grasp the Patriot System Operations and Maintenance concepts."

It typically takes around a year for US soldiers to complete training on the Patriot, though Pentagon spokesman Brig. Gen. Patrick Ryder said in January that the accelerated training timeline for Ukrainian troops would take "several months."

Ryder declined to get into specifics about the new timeline during a press briefing on Tuesday, saying only that the US is confident "we'll be able to get the Patriots there on an expedited timeline."

Troops training range in age from 19 to 67

The Ukrainian troops training are men and women ranging in age from 19-67. They arrived in mid-January and are set to compete the training in the coming days. The schedule was "aggressive," a Fort Sill official said, with the Ukrainians training daily from 7 a.m. to 6 p.m.

The announcement at the end of 2022 that the US would be providing a Patriot battery was a welcome one for Ukraine, who had repeatedly asked for the air defense capability. But experts warned that the system would not be a game changer overnight because of the significant training and logistical requirements that go along with it, as well as its limitations in scope.

"These systems don't pick up and move around the battlefield," retired Lt. Gen. Mark Hertling, former commander of US Army Europe, told CNN in December. "You put them in place somewhere that defends your most strategic target, like a city, like Kyiv. If anyone thinks this is going to be a system that is spread across a 500-mile border between Ukraine and Russia, they just don't know how the system operates."

The Ukrainians' day-to-day training in Oklahoma was overseen by the Army's 3rd Battalion, 6th Field Artillery Regiment, Morgan said, adding that the Ukrainian troops were "hand-picked by their country" and the "best of the best in what they do."

"I'm certain their actions these past months will save lives and alleviate suffering," Col. Marty O'Donnell, the spokesman for US Army Europe and Africa, said of the Ukrainian troops on Tuesday. "What they did matters — it matters to Ukraine, and to the world."

On Tuesday morning, John Kirby, the National Security Council's strategic communications coordinator, said the US was working to speed up the delivery of tanks to Ukraine.

"We're working on that. There's some changes that you can make to the process, to sort of speed that up," Kirby said on MSNBC. "The Pentagon is working as fast as they can, and they'll have more to say on adjustments they're making."

Ryder confirmed that the US would be sending M1-A1 tanks to Ukraine during Tuesday's briefing, saying the decision was made to help deliver the capability "as quickly as possible." Sending the older variant will allow the US to deliver the tanks by the fall, Ryder said.

He added that Ukraine would also be receiving similar armor and weapon capabilities to the M1-A2, including a 120 mm cannon and .50-caliber heavy machine gun.

The US had previously announced it would send the more modern M1-A2 version of the Abrams battle tank, but that would have required either building new tanks or modernizing existing older tanks, then training Ukrainian crews on the more advanced system. The M1-A2 has a newer digital targeting system that makes it a more capable tank, but it also required more training for Ukrainian troops to operate the more complex tank and to maintain the system.

The US still intends to send 31 M1-A1 Abrams tanks to Ukraine, the same number as previously announced and the size of a complete Ukrainian tank battalion.