President Obama on Tuesday poked fun at himself — and offered an explanation — a day after he was caught on a live television feed making candid remarks that he did not realize were being recorded.

Accounts of the incident spread rapidly across the Internet on Monday after TV cameras captured Obama telling Russian President Dmitry Medvedev that the sensitive issue of European missile defense could not be fully addressed in the heat of the 2012 presidential campaign.

“This is my last election,” Obama said, leaning close to Medvedev after a bilateral meeting held here as part of a nuclear security summit. “After my election, I have more flexibility.”

The comments drew condemnation from Republicans, including presidential candidate Mitt Romney, who charged that Obama was hiding his true intentions — a willingness to back down to the Russians on the defense plan— for political gain.

On Tuesday, the president defended his comments after being asked about them by a reporter. Obama called missile defense “extraordinarily complex, very technical” and said it would be virtually impossible to win broad consensus in Congress for any new major security agreements with Russia in an election year.

“First of all, are the mikes on?” Obama began, eliciting laughs.

Turning serious, he said: “I don’t think it’s any surprise that you can’t start that a few months before a 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 where a new president is going to be coming in in a little less than two months.”

He added: “Frankly, the current environment is not conducive to those kinds of thoughtful consultations. The stories you guys have been writing over the last 24 hours is probably pretty good evidence of that. I think we’ll do better in 2013.”

The political sniping over the president’s remarks has threatened to overshadow, at least back in the United States, his participation in the nuclear summit and even his administration’s admonishment of North Korea over its plan to launch a long-range rocket next month.

Sensing an opening, Republicans have pounced on Obama’s comments to try to put the president on the defensive. Romney said Monday that “President Obama signaled that he’s going to cave to Russia on missile defense, but the American people have a right to know where else he plans to be ‘flexible’ in a second term.”

Romney also called Russia the United States’ “number one geopolitical foe.”

White House Press Secretary Jay Carney called Romney’s comments “a little inaccurate.”

Obama stressed that he is committed to working with Russia to reduce nuclear stockpiles in both countries but that the two countries must build trust through negotiations on missile defense and other sticking points.

“I think everybody understands that — if they haven’t, they haven’t been listening to my speeches — I want to reduce our nuclear stockpiles,” Obama said Tuesday. “And one of the barriers to doing that is building trust and cooperation around missile defense issues. And so this is not a matter of hiding the ball. I’m on record.”

Later in the day, Obama met with Pakistan’s prime minister, Yousuf Raza Gilani, hoping to ease recent tensions between the two nations that have hindered efforts to achieve peace in Afghanistan.

According to Ben Rhodes, Obama’s deputy national security adviser for strategic communications, the president came away from the meeting with a good understanding of the Pakistani parliament’s ongoing review of the bilateral relationship.

Obama reiterated that Pakistan “has a constructive role to play” in Afghanistan’s peace process and told Gilani he looks forward to Pakistan’s participation in a summit of the International Security Assistance Force in May, Rhodes said.

Before the meeting, Obama said he wants to “achieve the kind of balanced approach that respects Pakistan’s sovereignty but also respects our concerns with respect to our national security and our needs to battle terrorists who have targeted us in the past.”