Brennan Linsley, Associated Press
On Saturday, presidential hopeful Sen. Barack Obama, D-Ill., waves to his supporters in Old San Juan, Puerto Rico, which holds the next Democratic primary on June 1.

SAN JUAN, Puerto Rico (MCT) — Barack Obama said Saturday that he accepted presidential nomination rival Hillary Clinton's explanation that she made an innocent gaffe in citing Robert F. Kennedy's June 1968 assassination as a justification for continuing her long-shot bid for the Democratic presidential nomination into June.

Clinton raised the analogy to the campaign-trail murder in response to a question Friday from the Sioux Falls Argus Leader editorial board in South Dakota about calls for her to quit her campaign against front-runner Obama. Her remarks rapidly provoked an uproar, and she apologized within hours.

Asked about Clinton's remarks in an interview with Radio Isla Puerto Rico while campaigning in the commonwealth, Obama attributed them to fatigue.

"I have learned that when you are campaigning for as many months as Senator Clinton and I have been campaigning, sometimes you get careless in terms of the statements that you make, and I think that is what happened here," Obama said. "Senator Clinton says that she did not intend any offense by it, and I will take her at her word on that."

Clinton's remark touched a raw nerve, particularly since anxiety over Obama's safety has been a frequent though mostly unspoken concern of many of his supporters, as well as party leaders.

His barrier-breaking candidacy has stirred concerns over racist threats, and the Secret Service judged the risk to his security high enough that it assigned a protective detail to him at an unusually early stage of the presidential campaign.

Many people who see a parallel between the promise of Obama's candidacy and the careers of the John F. Kennedy and Robert F. Kennedy also inevitably turn to their thoughts to the two brothers' early ends.

Clinton brought up Robert Kennedy's assassination as she sought to explain to the South Dakota newspaper why she was continuing her candidacy even though the odds are heavily against her success.

"My husband did not wrap up the nomination in 1992 until he won the California primary somewhere in the middle of June, right? We all remember Bobby Kennedy was assassinated in June in California. You know I just, I don't understand it," Clinton told the paper.

Clinton later issued a statement saying she was simply making a historical reference to nominations that were not resolved until late in the election season.

"I was discussing the Democratic primary history and in the course of that discussion mentioned the campaigns of both my husband and Sen. (Robert) Kennedy waged in California in June in 1992 and 1968 and I was referencing those to make the point that we have had nomination primary contests that go into June," she said. "That's a historic fact.

"The Kennedys have been much on my mind the last days because of Sen. Kennedy," she added, referring to Sen. Edward Kennedy's recent diagnosis of a brain tumor. "I regret that if my referencing that moment of trauma for our entire nation and in particular the Kennedy family was in any way offensive. I certainly had no intention of that whatsoever."

Both Obama and Clinton spent the first day of the three-day Memorial Day holiday weekend campaigning in the Caribbean Island of Puerto Rico, which holds the next Democratic primary on June 1.

Obama led a traditional caminata parade through the Spanish colonial historic area of Old San Juan as a music truck played reggaeton and salsa campaign songs, a staple of Puerto Rican politics.

"Un amigo presidente, porque respeta a nuestra gente" goes one of Obama's jingles, also a political custom in the Spanish-speaking territory. The words translate to: "A president friend, because he respects our people."

Obama avoided taking sides in the long-standing debate over whether the island should become a state, retain its commonwealth status or seek independence. He said the decision should be left to the territory's residents, a stand also taken by Clinton.

"I want to make sure that here in Puerto Rico the people of Puerto Rico are able to decide on the status of the island, and make sure that they are able to create the kind of government that they want," Obama said, drawing cheers.

Obama spent only 18 hours on the island, also including meetings with political officials and a roundtable with local veterans. He is not scheduled to make a return visit before the election. Puerto Rico does not have a vote in the November general election and Clinton is heavily favored to win the primary in the commonwealth.

Clinton held a town meeting in the western town of Aguadilla, Puerto Rico, and plans to remain Sunday for stops in the southern city of Ponce and in San Juan.