A US Bradley Fighting Vehicle (BFV) patrols the countryside of the Kurdish-majority city of Qamishli in Syria's northeastern Hasakeh province, on April 20, 2022.
Washington CNN  — 

There has been a “substantive” change in the type of weaponry the US and its allies are providing to Ukraine to meet Kyiv’s requests for firepower, two senior US officials tells CNN.

The US’s latest aid announcement included more offensive weapons, such as Bradley Fighting Vehicles and advanced long-range rocket systems, reflecting the nature of the battlefield in Eastern Ukraine and a belief that Ukraine sees a window to regain territory before Russia regroups, one of the officials said, describing the new weapons systems as giving the Ukrainians “much more capability.”

One US official also noted that Ukraine has abided by limitations on the use of the weapons the West has provided so far, tempering reservations about sending more capable systems.

US officials emphasized that the Ukrainians are developing and following their own strategy, and US moves are intended to support that strategy and meet their needs on the battlefield.

“We are in constant touch with Ukraine about what it needs to defend itself and we believe we are meeting the need. As the situation evolves, so does our assistance,” NSC spokesperson Adrienne Watson told CNN.

Last week, in the largest military aid announcement since the war began, the US said it was providing Bradleys, which one top Pentagon official said was meant to bolster Ukraine’s offensive fighting abilities.

Pentagon spokesman Brig. Gen. Patrick Ryder also said last week that Bradleys, which are armored vehicles that can carry troops into battle and can be equipped with TOW anti-tank guided missiles, will provide “a level of firepower and armor that will bring advantages on the battlefield as Ukraine continues to defend their homeland.”

‘Iron fist’

Experts agree that the Bradleys provide Kyiv with a significant new offensive capability.

“What I would imagine the Ukrainians will do is take these 50 Bradleys and put most of them in one battalion or one armored brigade … and create an iron fist that would be used to penetrate Russian linear defenses,” said retired Army Lt. Gen. Ben Hodges, former commander of US Army Europe and NATO Allied Land Command and currently a senior adviser for Human Rights First.

“We are positioning Ukraine to be able to move forward and retake territory,” Deputy Assistant Defense Secretary Laura Cooper added on Friday.

The Biden administration has thus far emphasized that they are supporting Ukraine’s defense against Russian attacks, particularly air defense, which Ryder said on Friday was still “a top priority.”

The “substantive” change in the weapons they’re providing gives Ukraine more offensive capability compared to early months of the war, one of the US officials said.

The changes, including providing advanced longer-range missile defense systems like the Patriot missile system and armored vehicles such as the Bradley which officials have described as a “tank killer,” follow Ukrainian forces demonstrating they can utilize the systems appropriately by not striking within Russian territory. The US has already provided other long-range systems like the High Mobility Artillery Rocket System, or HIMARS, which Ukraine recently used in a strike against Russian forces in the occupied city of Makiivka.

The US and its partners assess that Ukraine will benefit from expanding offensive operations now, to retake territory before Russia is able to regroup its forces for any of its own offensive operations.

On Friday, Cooper said that Russian President Vladimir Putin has “not given up his aims” of acquiring Ukrainian territory, but that the “reality of Russian weakness … has collided with those aims.” Ryder added that one of those weaknesses is Russia’s ability to defend the territory they’ve taken.

“And so, as you look at the US and the international response by providing the equipment, and importantly now the training that we’re providing, it does afford Ukraine an opportunity to change the equation on the battlefield and gain momentum and not only defend their territory, but hopefully take back territory,” Ryder said.

Advocates for putting more capabilities in the hands of Ukraine’s military say that now is the time to increase the capabilities Washington is providing to Kyiv. In a Washington Post op-ed on Saturday, former Secretary of State Condoleezza Rice and Secretary of Defense Bob Gates called for a “dramatic increase in military supplies and capability.” And the most important capability they need, Rice and Gates said, is armor.

Since the announcement of the Bradleys to Ukraine, there have been questions surrounding what could come next, namely if the US would consider M1 Abrams tanks. Asked about reluctance to provide Abrams tanks to Ukraine on Friday, Cooper told reporters that the administration is “always looking at what Ukraine needs” but that they have to be “cognizant of maintenance and sustainment considerations with tanks.”

“Certainly we know that the Abrams tank in addition to being a gas guzzler is quite challenging to maintain,” Cooper said.

The US is also conscious of domestic politics, with a GOP-controlled House less supportive of Ukrainian military assistance. House Republicans have long called for increased oversight of aid packages to Ukraine. Some, however, have taken a more aggressive approach and said they would oppose certain weapons packages.

CNN’s Haley Britzky contributed reporting.