The U.S. has in recent months transferred hundreds of thousands of artillery shells from its ammunition stockpiles in Israel to Ukraine, three current and former Israeli officials told Axios.

Why it matters: The ammunition that was transferred to Ukraine was part of a U.S. weapons stockpile that is pre-positioned in warehouses on Israeli soil as part of an agreement between the countries.

• The warehouses are locked and only U.S. military personnel has access to them. But according to the agreement between the countries, Israel can use this ammunition in a war scenario in short order under U.S. approval.

Of note: Israel was granted access to the ammunition during the war with Lebanon in 2006 and also during the 2014 Gaza conflict.

The big picture: The move was part of a wider effort by the Pentagon to resupply the Ukrainian army, which needs tens of thousands of artillery shells every month for its war against Russia in which artillery fire is a key component.

Driving the news: The transfer of the 155mm artillery shells from the U.S. stockpile in Israel to Ukraine was first reported by the New York Times.

• Israeli officials told Axios that the Pentagon raised the issue with the Israeli ministry of defense some four months ago.
• "It wasn't such a drama. It was a technical update for the protocol because it’s their ammunition and they don’t really need our permission to take it," an Israeli official said.

Between the lines: The Israeli officials said the main concern was that Russia would see this move as military aid by Israel to Ukraine.

• Since the beginning of the Russian invasion nearly a year ago, Israel has refused to supply Ukraine with weapons out of concern that the Kremlin would retaliate by limiting the freedom of operation of the Israeli air force against Iranian targets in Syria.

Behind the scenes: Yair Lapid, Israel’s prime minister at the time, and then-Defense Minister Benny Gantz conducted several meetings on the issue with senior officials from the national security council, IDF and Defence and Foreign Ministries.

• "The entire security establishment and intelligence community was in favor of this. First, because it is not really our ammunition and we can’t really say no without creating a big crisis with the Biden administration," a senior former Israeli official told Axios.
• The Israeli military told Lapid and Gantz that there was no immediate scenario in which Israel would need an emergency supply of 155mm shells, so the transfer wouldn’t harm Israel’s military preparedness, the three current and former Israeli officials said.
• The assessment of the Israeli defense establishment and intelligence community was that Russia wouldn’t see such a move as a policy shift by Israel because it is not Israeli ammunition, the officials said.