Ukrainian service members fire a shell from an M777 Howitzer at a front line, as Russia's attack on Ukraine continues, in Donetsk Region, Ukraine November 23, 2022.
CNN  — 

The United States has transferred American munitions stored in Israel for use in Ukraine and plans to send more soon, US and Israeli officials told CNN Wednesday.

A US official told CNN they have moved “some” of the 300,000 155-millimeter shells that the US and Israel agreed would be transferred, and that there are plans to move the remaining amount in the coming weeks.

Israel Defense Forces spokesperson Richard Hecht told CNN that the Americans notified the Israelis a while ago they were transferring munitions. Hecht said the munitions are US-owned, that their movements are “American business” and that they don’t need Israeli permission to move the munitions.

“In support of security assistance packages to Ukraine via the Presidential Drawdown Authority, the DOD has been able to transfer materiel and equipment while maintaining military readiness. Due to operational security considerations, we will not discuss the location or units providing the equipment or materiel,” Pentagon spokesman Brig. Gen. Patrick Ryder said in a statement. “As we provide aid to Ukraine, we are also working to replenish US inventories and backfill depleted stocks of allies and partners.”

The New York Times first reported the American military is tapping into its munitions stockpile stored in Israel for use in Ukraine, noting Israeli officials had initially expressed “concerns about appearing complicit in arming Ukraine.”

Israel has been walking a fine diplomatic line during Russia’s invasion of Ukraine. While Israeli leaders have condemned the invasion, supported Ukraine in the United Nations, sent humanitarian aid and taken in refugees, Israel has drawn a hard line at sending military aid, citing its own security sensitivities. Prime Minister Benjamin Netanyahu said before he took office at the end of December that he would review Israel’s policy on Russia’s war in Ukraine.

The strain on weapons stockpiles – and the ability of the US industrial base to keep up with demand – is one of the key challenges facing the Biden administration as the US continues to send billions of dollars of weapons to Ukraine to support its fight against Russia. CNN previously reported a US official said the stockpiles of certain systems are “dwindling” after months of sending supplies to Kyiv during the high-intensity war, as there’s “finite amount” of excess stocks which the US has available to send.

CNN reported in November that the US intended to buy 100,000 rounds of artillery ammunition from South Korean arms manufacturers to provide to Ukraine as part of a broader effort to find available weaponry for the high-intensity battles unfolding in Ukraine.

CNN’s Jim Sciutto, Jeremy Herb, Katie Bo Lillis and Oren Liebermann contributed to this report.