David Cameron is facing a demand to raise concerns about "serious and deteriorating" abuses of human rights, including evidence of torture, during a visit to the former Soviet republic of Kazakhstan.
Cameron will become the first British prime minister to make an official visit to the oil-rich republic as part of his mission to refocus British foreign policy on boosting trade links around the world.
He will meet the president, Nursultan Nazarbayev, who was re-elected in controversial circumstances in 2011. During the trip a series of business deals covering energy and transport are expected to be signed.
David Mepham, director of Human Rights Watch (HRW), has written to Cameron urging him to make strong representations on human rights.
He wrote: "Human Rights Watch has been documenting human rights abuses in Kazakhstan for over 15 years. We are very concerned about the serious and deteriorating human rights situation there in recent years, including credible allegations of torture, the imprisonment of government critics, tight controls over the media and freedom of expression and association, limits in religious freedom, and continuing violation of workers' rights."
HRW said defendants in a trial last year testified that they had faced beatings and suffocation after riots in Zhanaozen and that government critics were imprisoned after the protests.
A Downing Street spokesperson said: "When the prime minister goes abroad he has full and frank discussions with other foreign leaders. Where the UK has concerns about human rights or other issues he does not hesitate to raise them."
