SEOUL, South Korea (AP) -- President Barack Obama said Tuesday he is not trying to "hide the ball" in negotiations with Russia over U.S. plans for a missile defense shield in Europe, trying to put to rest a controversy over comments to Russia's leader that were picked up by an open microphone and quickly drew fire from Republican presidential contenders in America.
Republicans had pounced on Obama's remarks to Russian President Dmitry Medvedev on Monday that he would have more room to negotiate on the issue after the November presidential election, accusing the president of having a hidden agenda that could include concessions to the Russians if he is re-elected this fall.
Obama's conversation was picked up by a microphone without either leader apparently knowing.
"This is my last election," Obama was heard telling Medvedev, Russia's outgoing president. "After my election, I have more flexibility."
A day later, with election-year political machinery in full gear, Obama sought to clarify.
"I want to reduce our nuclear stockpiles. And one of the barriers to doing that is building trust and cooperation around missile defense issues," he said while he and Medvedev made a separate announcement about nuclear materials cleanup on the sidelines of a major security conference here.
"And so this is not a matter of hiding the ball," Obama said. "I'm on record."
Obama was prepared and eager to clarify his caught-on-tape words even at the risk of overshadowing his message for a second day about nuclear security efforts. In talking to reporters, however, he never answered a question about the presumptuous of plotting out 2013 strategy with Russia when, in fact, he must win election again for any of that to matter.
For Russia, the issues of nuclear weapons reduction and the proposed missile shield are related. Russian fears of new U.S. missiles at its doorstep in Europe have helped to stymie further progress on nuclear arms reductions after a breakthrough agreement two years ago.
Obama said he wants to spend the rest of this year working through technical issues with the Russians, and said it was not surprising that a deal couldn't be completed quickly.
"I don't think it's any surprise that you can't start that a few months before presidential and congressional elections in the United States, and at a time when they just completed elections in Russia, and they're in the process of a presidential transition," Obama told reporters Tuesday.
He also made light of the controversy, jokingly asking whether the microphones were switched on before he spoke.
"The only way I get this stuff done is if I'm consulting with the Pentagon, if I'm consulting with Congress, if I've got bipartisan support, and the current environment is not conducive to those kinds of thoughtful consultations," Obama said.
"I think we'll do better in 2013."
Neither Obama nor Medvedev knew they were being heard when they conferred quietly at what was billed as their last meeting of Medvedev's presidency. He leaves office in May, to be replaced by the incoming Vladimir Putin.
According to ABC News, Medvedev replied in English: "I understand. I will transmit this information to Vladimir," an apparent reference to incoming President Vladmir Putin.
The White House said Obama's words reflected the reality that domestic political concerns in both the U.S. and Russia this year would make it difficult to fully address their long-standing differences over the contentious issue of missile defense. Obama, should he win re-election, would not have to face voters again.
Obama's candid remarks Monday illustrated the political constraints that hem in any president who is running for re-election and dealing with a congressional chamber -- in this case, the House -- controlled by the rival party.
Republicans have fought Obama fiercely on health care, taxes and other issues. They are eager to deny him any political victories in a season in which they feel the White House is within reach, although Obama's remarks suggested he feels good about his re-election prospects.
Mitt Romney, the leading Republican contender to face Obama this fall, told a San Diego audience the unguarded comments were "an alarming and troubling development."
"This is no time for our president to be pulling his punches with the American people, and not telling us what he's intending to do with regards to our missile defense system, with regards to our military might and with regards to our commitment to Israel," Romney said.
Romney, a former Massachusetts governor who often faces charges of having been flexible on his own policies over the years, also issued a statement saying Obama "needs to level with the American public about his real agenda."
Obama campaign spokesman Ben LaBolt said Romney "is undermining his credibility by distorting the president's words."
Republican presidential candidate Newt Gingrich also questioned Obama's motives.
"I'm curious, how many other countries has the president promised that he'd have a lot more flexibility the morning he doesn't have to answer to the American people?" Gingrich said on CNN.
Rep. Mike Turner of Ohio, Republican chairman of the House Armed Services Subcommittee on Strategic Forces, wrote to the president requesting an "urgent explanation of (his) comments." Turner said Congress "has made exquisitely clear to your administration and to other nations that it will block all attempts to weaken U.S. missile defenses."
The Republicans' sharp remarks underscore increased willingness of politicians to criticize a president on a foreign trip. The old adage "politics ends at the water's edge" is a casualty of the nation's heightened partisanship in recent decades.
Obama said the way the Republicans seized on his open-mic comments only made his point that the atmosphere is too politicized right now to advance arms control with Russia.
Congress, as part of the fiscal 2012 defense authorization act, constrained Obama's ability to share classified U.S. missile defense information with Russia. Obama signed that legislation into law.
Putin said earlier this month that Washington's refusal to offer Moscow written guarantees that its missile defense system would not be aimed against Russia deepened its concerns.
AP White House Correspondent Ben Feller in Seoul, South Korea, Associated Press writers Kasie Hunt in San Diego and Donna Cassata in Washington contributed to this report. Babington reported from Washington.