The United States has imposed sanctions on five Russians, including the leader of Chechnya, under a US human rights law that has been a major irritant between Washington and Moscow. <br/><br/>The five Russians were targeted under the Magnitsky Act, passed by Congress in 2012 in response to the death of Russian lawyer Sergei Magnitsky. He died in prison after exposing a tax fraud scheme involving Russian officials, and the law named after him allows the US to target violators of human rights. <br/><br/>The latest additions include Ramzan Kadyrov, the head of Chechnya, a predominantly Muslim republic in southern Russia. The sanctions freeze any assets the individuals may have in the United States, and also bar Americans from doing any business with them.