President Donald Trump’s ultimatum to Russia to accept a peace deal in Ukraine within 50 days or face bruising sanctions on its energy exports has given the Kremlin extra time to pursue its summer offensive.

President Trump has effectively handed Vladimir Putin an extraordinary green light: 50 days to finish off his brutal summer offensive in Ukraine before facing any consequences.

Russia launched four missiles and 136 drones into Ukraine overnight into Monday morning, according to Ukraine's air force.

President Donald Trump is downplaying the possibility of sending Ukraine long-range weapons as Kyiv awaits an injection of U.S. weaponry that it hopes will help it beat back an intensifying Russian air offensive.

Daniel Martindale helped the Kremlin target Ukrainian troops and was then spirited out of eastern Ukraine by Russian special forces.

A Russian official says American Daniel Martindale has been rewarded with citizenship for spying on Ukraine, "by decree of our President Vladimir Putin."

The US president says he is "disappointed" in Putin and will be sending "top-of-the-line" weapons to Ukraine, via Nato.

"Putin's criminal war is getting closer to our borders," Polish Foreign Minister, Radosław Sikorski, said on Wednesday.