The Archbishop of Canterbury has condemned alleged atrocities in the Ukrainian town of Bucha.

Archbishop Justin Welby lamented the "loss of humanity" in a tweet in which he called for the killing to end. 

"With war comes the loss of our humanity - and that is laid bare for the world to see in Bucha," he said.

"May those leading the war of aggression against the people of Ukraine rediscover their humanity, and stop this obscene killing of God's precious children." 

Ukraine says that war crimes have been committed by Russian soldiers. 

In Bucha, a town close to capital Kyiv, there are reports of dead civilians being found with their hands tied behind their backs and signs of being killed execution style. 

Bucha Mayor Anatoly Fedorur said that retreating Russian forces executed at least 280 civilians. 

Ukrainian President Volodymyr Zelenskiy has used the word "genocide" to describe the atrocities being committed, and has said that his people are being "exterminated".

The International Criminal Court is already investigating allegations of war crimes and genocide in Ukraine.

In a report on Sunday, Human Rights Watch (HRW) said Russian troops were committing "laws-of-war violations" against civilians in occupied areas of the Chernihiv, Kharkiv, and Kyiv regions.

"These include a case of repeated rape; two cases of summary execution, one of six men, the other of one man; and other cases of unlawful violence and threats against civilians between February 27 and March 14, 2022," it said.

"Soldiers were also implicated in looting civilian property, including food, clothing, and firewood. Those who carried out these abuses are responsible for war crimes." 

Hugh Williamson, HRW's Europe and Central Asia director, said, "The cases we documented amount to unspeakable, deliberate cruelty and violence against Ukrainian civilians. 

"Rape, murder, and other violent acts against people in the Russian forces' custody should be investigated as war crimes."