Ukraine and the West have accused Russian troops of committing war crimes in its 11-week invasion of its neighbour, in which thousands of civilians have been killed. Russia has denied the allegations. However, social media posts could potentially be used as proof.

In a letter to Meta CEO Mark Zuckerberg, the leaders of the House Oversight and Foreign Affairs committees, Carolyn Maloney and Gregory Meeks, as well as two subcommittee chairmen, William Keating and Stephen Lynch, encouraged the company to preserve content posted on its sites that was related to the conflict. 

That content "could potentially be used as evidence as the US government and international human rights and accountability monitors investigate Russian war crimes, crimes against humanity, and other atrocities in Ukraine", the letter said.

In the wake of the withdrawal of Russian troops from districts north of Kyiv last month, officials have been looking at reports that civilians...