A prominent U.S. Republican senator has asked the defense secretary to tone down his criticism of Venezuelan President Hugo Chavez, suggesting it could hurt drug fighting efforts in the region.

The request was made in a letter Friday from Senator Arlen Specter of Pennsylvania to Secretary Rumsfeld, and follows the senator's meeting Wednesday with Mr. Chavez in Caracas.

The following day, Mr. Rumsfeld said during a South American visit there was evidence that Venezuela and Cuba were involved in Bolivia "in unhelpful ways." Political unrest in Bolivia has led to the resignation of two presidents there in the last two years.

Senator Specter says his meeting with Mr. Chavez led to diplomatic talks next week to resolve differences between narcotics officials, and a moratorium on adverse comments might be helpful.

Some information for this report provided by AP.