The U.S. has warned the United Nations that it believes Russia has plans to kill large numbers of critics, dissidents and “vulnerable populations” in Ukraine or send them to camps after an expected invasion, writes NBC NEWS.

The Kremlin denied the report on Monday, with Kremlin spokesman Dmitry Peskov calling it an “absolute lie”.

Ambassador Bathsheba Nell Crocker, the U.S. representative to the Office of the United Nations and Other International Organizations in Geneva, recently made the assertions in a letter to the U.N. High Commissioner for Human Rights, Michelle Bachelet, the contents of which were first reported Sunday evening by The Washington Post.

NBC News obtained the letter, which says, “We have credible information that indicates Russian forces are creating lists of identified Ukrainians to be killed or sent to camps following a military occupation”.

Crocker said in the letter that the U.S. believes Russia would “likely target those who oppose Russian actions, including Russian and Belarusian dissidents in exile in Ukraine, journalists and anti-corruption activists, and vulnerable populations such as religious and ethnic minorities and LGBTQI+ persons”.

The document warns of large-scale “human rights violations and abuses” and says protesters would also be met with unjust force.

“We also have credible information that Russian forces will likely use lethal measures to disperse peaceful protests or otherwise counter peaceful exercises of perceived resistance from civilian populations”, - the letter says.