The senior European official added that Europe was extremely reluctant to agree to Russia’s demand to block deliveries of weapons to Ukraine by its allies during any truce. That outcome would risk a situation where Russia was able to rearm during a cessation of hostilities, while Ukraine was prevented from doing so, the official said.

Putin has said he supports the US proposal for a pause to the conflict in principle but insists that a number of conditions need to be met before Russia can agree to halt its invasion. The Russian leader will probably agree to a truce, though he wants to make sure his terms are included first, Bloomberg reported on March 12.

The Trump administration has effectively already conceded Russian demands to keep control of occupied Ukrainian territory and for Kyiv to abandon its ambition to join the North Atlantic Treaty Organization. That has fueled European concerns that any deal the US president strikes with Putin will leave Ukraine weakened and vulnerable to Russia in the future.

The US is also likely to want Ukraine to accept effective neutral status and some limits on its army and weapons, in line with Russian demands, said Cliff Kupchan, a former senior State Department official who’s chairman of the New York-based Eurasia Group.