KYIV — Ukraine summoned a U.S. diplomat on Wednesday to explain the Pentagon’s decision to withhold already-agreed military aid that Kyiv warned is positive news for Russia.

POLITICO reported Tuesday that the Pentagon halted shipments of air defense missiles and other precision munitions to Ukraine due to worries that U.S. weapons stockpiles have fallen too low.

White House Deputy Press Secretary Anna Kelly said in a statement that the decision “was made to put America’s interests first following a review of our nation’s military support and assistance to other countries across the globe.” 

But the aid halt — the second since Donald Trump took office in January — leaves Ukraine on the back foot as it fends off growing numbers of Russian drone and missile attacks pounding its cities every day.

“Any delay or slowing down in supporting Ukraine’s defense capabilities would only encourage the aggressor to continue war and terror, rather than seek peace,” Mariana Betsa, the deputy foreign minister of Ukraine, said in a statement on Wednesday. 

Ukraine’s Foreign Ministry called in John Ginkel, the deputy chief of mission at the U.S. Embassy in Ukraine, for talks on Wednesday. The ministry expressed gratitude for U.S. aid, but also discussed defense supplies and further contacts between Ukraine and the United States.

The weapons pause was greeted positively by Russia.

“The fewer arms supplied to Ukraine, the closer the end of the special military operation will be,” Kremlin spokesperson Dmitry Peskov told reporters.

The decision to withhold some of the aid approved by the previous administration of President Joe Biden was made in early June, and officials in Kyiv are scrambling to work out the impact.

“Ukraine has not received any official notifications about the suspension or revision of the delivery schedules of the agreed defense assistance, so we proceed from the actual data and check the details of each element in the delivery,” Ukraine’s Defense Ministry said in a statement on Wednesday.

NATO Secretary-General Mark Rutte told Fox News that while he understood the U.S. need to safeguard its stockpiles, he warned: “In the short term Ukraine cannot do without all the support it can get when it comes to ammunition and air defense systems.”

Trump’s policy

The first halt in arms aid to Ukraine happened in March, when Trump was trying to strong-arm Kyiv into negotiations with Russia. This time, the decision was driven by the Pentagon’s policy chief, Elbridge Colby. After a review of Pentagon stockpiles, he raised concerns that the total number of artillery rounds, air defense missiles and precision munitions was sinking. Colby is a longtime critic of the U.S. arming Ukraine.

Some of the items being withheld back are PAC-3 missiles for Patriot air defense systems, precision artillery rounds, Hellfire and other missiles that Ukraine launches from its F-16 fighters and drones.

“Ukraine must maintain stability, continuity, and predictability in the provision of coordinated defense assistance, primarily in the area of ​​strengthening air defense systems,” the Ukrainian Defense Ministry said.

This comes as Russian troops are rapidly advancing in Ukraine while the number of air attacks against cities far from the front lines soars.

“Halting of PAC-3 SME interceptors for Patriot is alarming — against the background of both the increase in ballistics production in Russia, and supplies from [North Korea] and the vulnerability of a bunch of large frontline cities to this,” said Mykola Bielieskov, research fellow at the National Institute for Strategic Studies.

He added that the stoppage was “not OK,” because Ukraine could have survived for the next few years on assistance under the Ukraine Security Assistance Initiative, a U.S. program he said has contracted with manufacturers for about $35 billion in arms and ammunition.

The argument that the U.S. is running short of missile interceptors doesn’t hold water, said Sidharth Kaushal, senior research fellow at London’s Royal United Services Institute.

While the U.S. has sent a considerable number of Patriot interceptors to Ukraine, it has replenished stocks through buyback schemes from Japan, and more recent shipments were diverted from export customers rather than the Pentagon’s own inventory, Kaushal said.

The U.S. produces about a dozen Patriot systems a year, and its production of PAC-3 interceptor missiles surged by about 30 percent last year to around 500. That means inventory stockpiles are not critically low.

“While precise numbers on stockpiles are not public, it is not necessarily the case that stockpiles of missiles such as PAC-3 have been significantly depleted in the sense of a significant reduction in absolute numbers,” said Kaushal.

However, the decision does reflect the shift in U.S. priorities.

“The scarcity is relative and not absolute and driven by increases on the demand rather than the supply side,” Kaushal said. “Also, since initial diversions of Patriot came at the expense of export partners, including some in the Middle East, there may be a belief (and indeed a contractual obligation) to deliver interceptors to partners who are in some cases within range of Iranian SRBMs.”

The United States on Monday announced the approval of a $510 million sale to Israel of bomb guidance kits and related support.

This article has been updated.