* Promises to fix immigration quickly in second term
* Says Republican rival's approach "very troublesome"
* Secret Service scandal overshadows trade message
CARTAGENA, Colombia April 14 (Reuters) - U.S. President Barack Obama, taking his re-election campaign south of the U.S. border, promised on Sa turday to pursue long-promised immigration reform early in a second term and slammed his White House rival Mitt Romney's stance on the issue as "troublesome."
Obama is spending the weekend in Cartagena, Colombia, meeting with Latin American political and business leaders in a bid to strengthen economic ties with the region and convince Hispanic voters back home he cares about the region.
But a scandal involving allegations of misconduct by Secret Service agents charged with protecting the president threatened to overshadow the trade themes Obama hoped to highlight at the Summit of the Americas.
The Secret Service confirmed agents had been recalled but offered no details. U.S. media have reported the alleged misconduct involved prostitution.
Obama did not address the incident in his remarks to a business forum on Saturday morning, focusing instead on the potential gains for American businesses from exporting to an increasingly stable and prosperous Latin America.
"The days when we could think of each of our economies in isolation, those days are over," Obama said.
White House spokesman Jay Carney told reporters the Secret Service incident had not been a distraction for Obama, but he added, "It has been much more of a distraction for the press."
Obama, who arrived in Colombia on Friday, is courting the support of Hispanic voters in battleground states like Florida, Nevada and Colorado before the Nov. 6 election. His campaign considers Latinos a potentially pivotal voting bloc.
In an interview with the Spanish-language television network Univision, Obama faulted a divided and unpopular Congress for the lack of immigration progress to date and promised to pursue reforms as a first priority if re-elected.
"I can promise that I will try to do it in the first year of my second term," he said,
Although the Democratic president is polling ahead of Romney - the Republican Party's likely White House candidate - among Latino voters, many in the Hispanic community are frustrated he has failed to enact promised immigration reforms and think Obama has paid too little attention to Latin America while in office.
In the Univision interview, Obama warned that Romney would pursue "troublesome" immigration reforms if he were president.
"We now have a Republican nominee who said that the Arizona laws are a model for the country," Obama said, referring to the state's laws that call on police to check the immigration status of people they suspect of being in the country illegally.
"Very troublesome," he added. Critics of Arizona's approach say it could lead to ethnic profiling and Obama said it allowed people to be stopped "based on an assumption."
Andrea Saul, a spokeswoman for Romney, said the former Massachusetts governor was committed to repairing the U.S. immigration system, "respecting those who are waiting patiently to come here legally, and finally ending illegal immigration in a civil and resolute manner."
She stressed Obama had also promised in 2008 to tackle immigration reform in his first year in office but failed to do so. "President Obama only talks about immigration reform when he's seeking votes," she said.
On Saturday, Obama pushed a message on trade and bolstering economic ties at a gathering with business leaders on the sidelines of the Summit of the Americas.
Participating in a panel with Brazilian President Dilma Rousseff, Obama said that as Brazil continued to grow, more people there would want to buy U.S. goods such as iPads made by Apple Inc - also joking Brazilians may want to buy more airplanes made by Boeing Co.
"Embraer," Rousseff retorted, to laughter. Boeing and Brazil's Embraer SA are longtime rivals in the aerospace sector.