John McCain said he would support a hemisphere-wide trade agreement while traveling in Colombia Wednesday, as his aides played political football with Barack Obama's campaign over the Republican candidate's trip to Latin America.

The presumptive presidential nominee spoke to reporters after touring a Colombian port Wednesday morning to observe the country's drug intervention efforts, and meeting the night before with President Alvaro Uribe.

McCain said he's committed to making sure Americans who have lost jobs to foreign competition find new employment, but stressed that a protectionist attitude would only hurt the U.S.

"I would like to see a hemispheric free trade agreement," McCain said. "I would like to see our continued assistance to countries like Colombia."

McCain said "history shows that isolationism and protectionism has very unpleasant consequences."

McCain was in the country when Colombia freed Ingrid Betancourt and three U.S. military contractors from leftist guerrillas, but he didn't learn of the rescue mission's success until he was aboard a flight to Mexico. Uribe called McCain to inform him of the success.

"He told me some of the details of the rescue, the dramatic details," McCain told reporters. "It's a very high-risk operation. I congratulate President Uribe, the military and the nation of Colombia."

The three-day trip to Colombia and Mexico inevitably underscored policy differences between McCain and Obama.

McCain is a free-trade advocate, while Obama says treaties like the North American Free Trade Agreement should be renegotiated.

Though McCain pledged not to attack Obama during his overseas visit, he readily chided his rival on the flight to South America, and on Wednesday the candidates' campaigns traded fire over the trip.

"(McCain's visit) lacks the sustained follow-through. The trip -- it's a photo op," Dan Restrepo, an Obama adviser on Latin American policies, said on a conference call.

The Obama campaign sent out a lengthy e-mail Wednesday morning saying McCain's support of the Colombia Free Trade Agreement, which Obama opposes, "underscores his insistence on continuing George Bush's failed economic policies."

The trade deal has stalled in the House of Representatives amid concerns about continuing intimidation and violence against labor leaders in the country. Thirty-one trade unionists have been murdered in Colombia so far this year, eight fewer than all of last year, according to the Medellin-based Escuela Nacional Sindical, a labor research institute.

Deals like NAFTA are also unpopular in American industrial states reeling from lost jobs.

"Unlike John McCain and George Bush, Obama does not believe that free trade is ... the goal in and of itself. The goal is to help Americans prosper and compete in the global market," the Obama campaign said.

McCain spokesman Brian Rogers said in a statement that Obama was "pandering" over his position on NAFTA.

"Barack Obama's shifting positions on free trade won't add more jobs or get our economy back on track," he said.

Obama said during the primary and repeated Tuesday that he would renegotiate NAFTA with the leaders of Canada and Mexico. However, Obama recently told Fortune magazine that "sometimes during campaigns the rhetoric gets overheated and amplified," and that he doesn't want to do anything "unilaterally" with the trade agreement.

Meanwhile, the Arizona senator got in several plugs for the proposed trade deal with Colombia, suggesting the tariffs imposed on American goods now exported to Colombia would disappear under the agreement -- creating jobs in the United States instead.

McCain also stressed the fight against the drug trade and other mutual concerns of the United States and Latin America.

McCain met with Uribe Tuesday night at the Colombian leader's seaside retreat. The two talked for nearly two hours and addressed the country's problematic human rights record, McCain said.

Speaking to reporters, Uribe said he and McCain had discussed Obama and what Uribe described as "positive" comments by the Illinois senator about Colombia. It was unclear what Uribe was referring to.

Pressed to elaborate, McCain said he and Uribe hadn't discussed the presidential campaign but agreed on the importance of bipartisanship in dealing with international matters.

The Arizona senator was also meeting with cabinet ministers and business leaders. He left Wednesday afternoon for Mexico City.

The Arizona senator is accompanied on the trip by his wife, Cindy, and two colleagues and top supporters of his presidential effort, Sens. Lindsey Graham, R-S.C., and Joe Lieberman, an independent from Connecticut.

FOX News' Mosheh Oinounou and The Associated Press contributed to this report.