United States President Joe Biden has informed his Ukrainian counterpart, Volodymyr Zelenskyy, that Washington will provide Kyiv with ATACMS long-range missiles, US broadcaster NBC News has reported.

Ukraine has repeatedly asked the Biden administration for the long-range Army Tactical Missile Systems (ATACMS) to help hit supply lines, airbases and rail networks deep behind Russia’s front lines in occupied regions of Ukraine.

But the White House has not announced a decision to provide Ukraine with the ATACMS system and the missiles were not publicly discussed when Zelenskyy visited Washington, DC on Thursday for talks with Biden, even as the US announced a new $325m military aid package for Kyiv.

The White House and the Pentagon declined to comment on the NBC report on Friday.

The Pentagon also declined to say whether any promise of ATACMS was given to Zelenskyy during his meetings on Thursday at the Department of Defense, saying: “In regards to ATACMS, we have nothing to announce.”

A date for delivery of the ATACMS was not revealed, according to NBC.

Russia’s Ministry of Foreign Affairs warned earlier this month that the supply of longer-range missiles to Kyiv would cross a “red line” and the US would be viewed as “a party to the conflict” in Ukraine if it did provide such weapons.

Zelenskyy did not answer directly when asked about the NBC reports on ATACMS, but he noted that the US was the biggest single supplier of weaponry to Ukraine.

“We are discussing all the different types of weapons – long-range weapons and artillery, artillery shells with the calibre of 155mm, then air defence systems,” Zelenskyy said, speaking through an interpreter.

“We have a comprehensive discussion and [we] work with the United States at different levels,” he said.

The Washington Post also reported that the US plans to provide Ukraine with a version of the ATACMS that will be armed with cluster bomblets rather than a single warhead, citing several unnamed sources familiar with the deliberations, and that can fly up to 306km (190 miles).

ATACMS is designed for “deep attack of enemy second-echelon forces”, a US Army website states, and could be used to attack command and control centres, air defences and logistics sites well behind the front line.