[新闻背景]U.S. Defense Secretary Leon Panetta heads to South America as part of Washington’s efforts to build partnerships in the region in the fight against drug trafficking and terrorism.  But the U.S. defense chief will also deal with the backlash of the scandal involving U.S. security personnel and Colombian prostitutes.

It is a region that is often out of U.S. headlines. But now, the worry that drug and human smuggling networks in the area may turn into a terrorist corridor is driving U.S. leaders to point their attention South.

This month, President Barack Obama attended the Summit of the Americas in Colombia, and his Secretary of Defense, Leon Panetta, is paying visits to Colombia, Brazil, and Chile - nations with which Washington has longstanding partnerships.

“This is a way of making contact and dealing with the region at a time when there’s growing concern over the ability of many countries to be able to handle the threat posed by transnational crime and, specifically, drug trafficking organizations,” said Steve Johnson, a former Pentagon official specializing in Latin America.

One U.S. concern is Venezuela’s military buildup and the country’s partnership with Iran.  

Reports of the deteriorating health of Venezuelan leader Hugo Chavez and the country’s elections this year have Washington watching for signs of instability.  

Venezuela is not on Panetta’s itinerary, but analysts expect it to be an underlying factor in his meetings.

“The important thing is not to overplay it, to give more importance to it than it really deserves, but at the same time to take it seriously so that when we deal with other countries we might be able to encourage them to keep an eye on it, to cooperate with us in trying to have a better understanding of what is going on,” Johnson said.

The U.S. defense secretary goes to Colombia days after allegations that U.S. military personnel, along with Secret Service agents assigned to guard President Obama, solicited prostitutes they met at a strip club in Cartagena - the site of the summit.

Some in Colombia complain the affair distracted attention from the meeting.

The U.S. military’s top officer, General Martin Dempsey, called it an embarrassment.

“We let the boss down because nobody’s talking about what went on in Colombia other than this incident,” Dempsey said.

Panetta hopes to turn attention back to the issues of drug trafficking and anti-terror efforts.