Russia warns US of repercussions if it sends more arms to Ukraine – reports

Diplomatic note believed to talk of ‘unpredictable consequences’ as US readies $800m of military hardware

Helicopters will be among the increasingly heavy-duty military equipment the Biden administration is sending to Ukraine. Photograph: Jeff J Mitchell/Getty Images

Helicopters will be among the increasingly heavy-duty military equipment the Biden administration is sending to Ukraine. Photograph: Jeff J Mitchell/Getty Images

Russia sent a formal warning to the US not to send more arms to Ukraine or it could face “unpredictable consequences”, it has been reported.

According to the Washington Post, Moscow sent a diplomatic note, a démarche, warning that US and Nato deliveries of the “most sensitive” weapons systems to Ukraine were “adding fuel” to the conflict there and could bring “unpredictable consequences”.

A spokesperson said the state department did not confirm any diplomatic correspondence as a matter of course, and made clear that the US would continue to send arms to Ukraine.

“What we can confirm is that, along with allies and partners, we are providing Ukraine with billions of dollars worth of security assistance, which our Ukrainian partners are using to extraordinary effect to defend their country against Russia’s unprovoked aggression and horrific acts of violence,” the spokesperson said.

The Russian embassy in Ukraine did not respond to a request for comment.

The US is preparing to send the latest $800m (£610m) tranche of military aid to Ukraine, bringing to $2.6bn the total since the start of the war. The Biden administration has also made clear that it was sending increasingly heavy and sophisticated equipment, including helicopters, aerial and marine drones, and long-range 155mm howitzers, while training Ukrainian soldiers in their use.

The US is also sending additional anti-tank and anti-aircraft missiles of the sort that have contributed to the war effort so far in Ukraine. The Ukrainians claim to have sunk the Russian Black Sea fleet flagship Moskva on Thursday using Ukrainian-developed Neptune missiles. The UK has promised to send more anti-ship missiles to replenish stockpiles. Military experts believe that Ukraine’s anti-ship missile systems are what has deterred Russia up to now from attempting an amphibious landing around Odesa.

It is unclear whether Moscow has sent similar diplomatic notes to European countries. On Thursday, the German vice-chancellor, Robert Habeck, appeared to back down on his demands earlier in the week for the Ukrainian army to be provided with what it needed as soon as possible.

Habeck cited concerns about Russian reprisals. “Heavy weapons are synonymous with tanks, and all Nato countries have so far ruled this out to not become targets themselves,” he told Politico.

Nevertheless, the Czech Republic has already sent T-72 tanks and tracked armoured personnel carriers while the US is sending helicopters and howitzers.