The International Crisis Group says the recent killing of a prominent Kyrgyz journalist raises questions about Uzbekistan's authoritarian government.
In a report released Thursday, the Brussels-based advocacy group says there are what it calls "strong indications" that Uzbek security forces were involved in the murder of Alisher Saipov.
The 26-year-old reporter - known for his investigative work - was shot at close range last year as he left his office in the Kyrgyz city of Osh.
Saipov was the founder of an Uzbek-language newspaper. He also reported for the U.S.-funded Voice of America and Radio Free Europe/Radio Liberty.
In its report, the ICG says the United States and the European Union should not seek further engagement with Uzbekistan.
The group cites recent visits to Tashkent by the EU's special representative for Central Asia, Pierre Morel and the head of U.S. Central Command, Admiral William Fallon as signs of improved relations.
Relations with Tashkent soured in 2005 after the government's bloody crackdown on protesters in the city of Andijan.
Uzbekistan's authoritarian President Islam Karimov won a new term in office last year. International monitors say the elections were undemocratic.