Nov. 6 (Bloomberg) -- Senator George LeMieux of Florida is using Senate rules to block a vote on President Barack Obama’s nominee for ambassador to Brazil, U.S. Senate Republican and Democratic aides said.

The Republican aide, who spoke on condition of anonymity, said LeMieux, a Republican, was delaying a vote to confirm Thomas Shannon, currently the State Department’s top diplomat for Latin America, over the administration’s decision to initiate talks with Cuba on migration and direct mail service.

The Democratic aide confirmed the so-called hold had been placed by LeMieux, although the aide was unfamiliar with the reasons for the delay. State Department spokesman Ian Kelly expressed disappointment that Shannon’s nomination was being blocked without saying who was behind the action.

Brazil is Latin America’s largest country and economy and of growing importance to the U.S. in the region, on matters from peacekeeping to energy to trade.

LeMieux, in an e-mailed statement, said he intends to meet with Shannon to “discuss my concerns about his nomination and U.S. foreign policy” in Latin America. He didn’t confirm or deny he was blocking a vote on the nomination.

The hold was placed immediately after Senator Jim DeMint, a South Carolina Republican, lifted his own three-month objection on Shannon and Arturo Valenzuela to replace him as assistant secretary of state for the Western Hemisphere.

DeMint said he received assurances that the U.S. would recognize the outcome of the scheduled Nov. 29 presidential election in Honduras regardless of whether deposed President Manuel Zelaya is reinstated. DeMint has said Zelaya was trying to impose a dictatorship with support from Venezuelan President Hugo Chavez.

Valenzuela was confirmed late yesterday by Senate voice vote.

In August, Florida Governor Charlie Crist chose LeMieux, a former chief of staff, to serve out the U.S. Senate term of Republican Mel Martinez, who resigned.

To contact the reporter on this story: Joshua Goodman in Rio de Janeiro jgoodman19@bloomberg.net

Last Updated: November 6, 2009 15:29 EST