The Kremlin leader, buoyed by his diplomatic success in Alaska, is treading carefully around US President Donald Trump. He hasn't shifted from his hard-line approach, while the Russian military is escalating its offensive.

The US president conceded the war in Ukraine was "tough to solve" after several days of high-level talks.

Meetings in Alaska and Washington were high on pomp and low on breakthroughs, but there were two potentially significant developments.