Thousands of Ukrainians are being “abducted and taken” to Russia, the chairman of Britain’s foreign affairs committee said on Monday.
Senior Conservative MP Tom Tugendhat branded the “deportations” as war crimes.
He demanded that the Kremlin explain to where “#TheTaken” were being transported.
Civic chiefs in besieged Mariupol said last Thursday that about 15,000 civilians had been illegally deported to Russia since Vladimir Putin’s forces seized parts of the southern port city.
“Residents of the Left Bank district are beginning to be deported en masse to Russia. In total, about 15,000 Mariupol residents have been subjected to illegal deportation,” said Mariupol city council.
Russian news agencies have also reported that convoys of buses have carried hundreds of people from the city on the Azov Sea, which has been largely destroyed by shelling and air strikes, to Russia.
Mr Tugendhat suggested the deportations were more widespread.
He tweeted: “Across Ukraine thousands are being abducted and taken to Russia. These deportations are war crimes.”
He spoke out shortly after Ukrainian president Volodymyr Zelensky claimed Russian troops had killed several mayors who they had seized in his country.
“They are kidnapping the mayors of our cities,” he said in an interview with The Economist.
“They killed some of them. Some of them we can’t find. Some of them we have found already, and they are dead. And some of them were replaced.”
Suggesting a special Russian military squad was targeting civic chiefs, he added: “The same people are carrying out these operations.”
Mr Zelensky is believed to have himself survived several attempts on his life, with Russian “saboteur” teams said to have infiltrated into the capital Kyiv.
The Kremlin, which previously said it was not planning to invade Ukraine, denies forcibly taking refugees from its neighbouring wartorn country.
