The 23 Russian diplomats expelled by the British prime minister over the nerve gas poisoning of a former Russian spy on UK soil piled out of the embassy in London on Tuesday hauling suitcases and pet cages to board buses for their return trip home.

Prime Minister Theresa May last week ordered the diplomats, who she said were undeclared intelligence agents, out of the country after blaming Moscow for being behind the poisoning of Sergei Skripal and his daughter earlier this month with a Soviet-era nerve gas.

The attack was the first known use of the lethal toxin – identified as Novichok – in Europe since World War II.

Russia, which has denied involvement and claims it doesn’t have chemical weapons, over the weekend ordered 23 British diplomats out of the country in a tit-for-tat retaliation.

“Let’s stay sober-minded and first of all wait for proof from Britain” that Russia was to blame, President Vladimir Putin’s spokesman Dmitry Peskov said Tuesday when asked if Moscow had evidence proving its innocence.

May is expected to meet with Britain’s National Security Council later Tuesday to discuss more measures against Russia.

Skripal, 66, and his daughter, Yulia, 33, remain hospitalized in critical condition after being found unconscious on a bench in Salisbury on March 4.

With Post wires