U.S. President Donald Trump's decision to ramp up arms shipments to Ukraine is a signal to Kyiv to abandon peace efforts, Russia said on Thursday, vowing it would not accept the "blackmail" of Washington's new sanctions ultimatum.

President Trump reportedly questioned Ukrainian President Volodymyr Zelensky about whether Kyiv could blast Moscow and St Petersburg, but later indicated publicly that Russia’s capital should be off limits.

The war has shown no signs of abating despite Trump setting a September 2 deadline for Russian President Vladimir Putin to reach a ceasefire deal with Ukraine