The Pentagon has decided to provide High Mobility Artillery Rocket Systems (HIMARS) to Ukraine due to the nature of the conflict changing to an "artillery duel", Under-Secretary of Defense for Policy Colin Kahl told a press briefing on Wednesday.

"The current stage of the conflict is about three months old, and the nature of that conflict has shifted. The priorities that Ukrainians have had, and what we thought have been most relevant to enable the Ukrainians to push back have changed over time," Kahl said. "As the conflict shifted to the East, as I said, it's become an artillery duel." 

US President Joe Biden announced earlier today that his country would provide Ukraine with more advanced rocket systems and munitions, which include HIMARS rocket systems.

Biden had stated on Monday that Washington would not provide Kiev with weapons capable of targeting Russian territory.

A senior administration official told reporters that the US would send M142 HIMARS, which have a range of approximately 77 km. He added that the missiles are part of a weapons package for Ukraine valued at $700 million.

In the initial phase of the conflict, Kahl said, especially as the Ukrainians were trying to repel the Russian forces in and around Kiev, Washington was heavily providing anti-armor systems, such as Javelin missiles and anti-air systems like Stingers.

"[T]hat assistance proved decisive in stymieing the Russian attempt to take and keep Kiev," he explained.

The challenge facing the Ukrainian forces was relying on Soviet legacy weapons systems, Kahl stressed, noting that at some point, it became impossible for the United States to resupply them with artillery systems and ammunition. 

The United States now prioritizes the shift toward supplying Kiev with 155-millimeter artillery systems, providing M777 howitzers to Ukraine, Kahl said.

“So, that was as the fight shifted to an artillery duel. The first thing was to get these Howitzers into the fight, and now we're shifting to HIMARS,” he explained. 

The HIMARSs are the centerpiece of this $700 million package that was unveiled today, which includes "Javelin anti-tank missiles, Stinger antiaircraft missiles, powerful artillery and precision rocket systems, radars, unmanned aerial vehicles, Mi-17 helicopters and ammunition," Biden said in his op-ed published in The New York Times.

The US has sent more than $5 billion in military supplies to Ukraine since Biden took office in 2021, according to a senior Biden administration official.

Department of State spokesperson Ned Price revealed Tuesday that his country was still considering a range of weapon systems for Ukraine that the latter could use against the Russian forces.

Moscow had sent a formal diplomatic note to the United States warning that Washington and Brussels' arms shipments were adding fuel to the fire of the war in Ukraine, stressing that this matter could bring upon "unpredictable consequences".