The concerns stem from a government crackdown last year in the former Soviet Union republic that led to the deaths of hundreds of Uzbeks.
U.S. Sen. John McCain, R-Ariz., and Rep. Christopher Smith, R-N.J., plan to introduce legislation calling for limitations on U.S. funding to Uzbekistan unless the Uzbek government permits a credible investigation into the May 13, 2005, killings in the city of Andijon, the International Herald Tribune reports.
The bill would ban travel visas for certain Uzbek officials, including Karimov, and restrict U.S. munitions exports to that country.
McCain, who may seek his party's 2008 presidential nomination, says the Bush administration has been too accommodating to Uzbekistan for too long, the report said.
The Uzbek government maintains that the May events have been misrepresented, and blames Islamic terrorists for trying to destabilize the country.