U.S. Secretary of State John Kerry on Sunday met Uzbekistan's autocratic ruler and officials from other Central Asian states accused of being among the world's worst human rights offenders.

But in the talks in the ancient city of Samarkand, he tempered any public criticism as he sought deeper U.S. ties with the region seen increasingly as lying in the shadow of an assertive Russia and exposed to Islamist militancy.

Kerry was in Samarkand to meet his five Central Asian counterparts and reassure them of continued U.S. engagement in the strategic region.