Russian President Vladimir Putin has illegally annexed four Ukrainian regions and vowed to use "all the power and all the means" at his disposal to defend them.
"This is the will of millions of people," he said in a speech before hundreds of dignitaries in the St George's Hall of the Kremlin.
The ceremony took place three days after the completion of hastily staged referendums in which Moscow's proxies in the occupied regions claimed majorities of up to 99% in favour of joining Russia.
