President Donald Trump ordered a pause to all military aid to Ukraine, turning up the heat on Volodymyr Zelenskiy just days after an Oval Office blowup with the Ukrainian president left the support of his country’s most important ally in doubt.

The US is pausing all current military aid to Ukraine until Trump determines the country’s leaders demonstrate a good-faith commitment to peace, according to a senior Defense Department official, who asked not to be identified discussing private deliberations. 

The official said all US military equipment not currently in Ukraine would be paused, including weapons in transit on aircraft and ships or waiting in transit areas in Poland. Trump ordered Defense Secretary Pete Hegseth to execute the pause, the person said.

Trump is pushing for a quick deal to end the war triggered by Russia’s invasion of its neighbor three years ago. But when Zelenskiy pushed in an Oval Office meeting last week for security guarantees to ensure Russia doesn’t violate any agreement, Trump angrily told him to come back when he’s ready for peace. 

That sent European allies racing to come up with plans to keep Ukraine supplied with weapons, as well to provide peacekeepers for a deal. But Europe lacks many of the arms and other capabilities that the US now provides. Allied officials have said supplies of weapons are likely to last only until summer. 

Just how much aid is affected by Trump’s order wasn’t immediately clear.

Trump came into office with $3.85 billion remaining in funding from the previous administration in so-called presidential drawdown authority from US inventories. It has remained unclear whether the Trump administration would actually use the money for Ukraine, particularly given US weapons stockpiles are running low and need to be replenished. 

Monday’s move extends beyond simply letting that funding expire, but threatens aid that is already being delivered or fulfilled. That includes the delivery of critical munitions, hundreds of guided multiple launch rocket systems and anti-tank weapons and other capabilities. Cutting off existing contracts with industry may also require the US to pay some form of break fee to companies who have started filling the orders. 

The US and Ukraine were due to sign a deal that would allow the US to a large share of future natural resources revenues from the war-battered nation but the deal appeared to fall apart after Friday’s meeting.