WASHINGTON - President Obama signaled Friday that he may halt the National Security Agency's collection and storage of millions of Americans' phone records and instead require phone companies to hold the data.

Speaking at a White House news conference near the end of a very difficult year, Obama said that he would have a "pretty definitive statement" on proposed NSA reforms in January, following his family's annual holiday break in Hawaii.

His remarks suggested that Obama's views have changed significantly since details of the NSA's far-reaching surveillance programs were publicly revealed in June. He said he believed his administration has struck the right balance between intelligence gathering and privacy protection but acknowledged that concerns about the potential for abuse may make it necessary to rein in the programs to restore public trust.

"The environment has changed," Obama said. He said that it "matters more that people right now are concerned," and added, "Just because we can do something doesn't mean we necessarily should."

During the 60-minute news conference, Obama also reiterated his claim of personal responsibility for the disastrous rollout of his health-care law. In addition, he expressed optimism that he could advance his agenda in 2014, beginning with immigration reform.

"I think 2014 needs to be a year of action," Obama said.

The president said his NSA review, based on the assessments of intelligence officials and other officials inside and outside of the federal government, would determine which programs to maintain or eliminate, both domestically and internationally.

An independent White House panel released a report this week questioning whether the NSA's sweeping collection of personal data had played any meaningful role in preventing terrorist attacks.

A federal judge also ruled that the data collection was probably unconstitutional.

Obama acknowledged that the United States needs to provide "more confidence" to the international community amid widespread outrage over revelations of U.S. spying on many foreign allies.

During the news conference, Obama sought to grapple with a year of partisan turmoil in Washington and his inability to advance an ambitious second-term domestic policy agenda through Congress. Initiatives on gun violence and immigration failed or stalled in the face of Republican opposition, and the president was unable to prevent broad spending cuts known as the sequester or a partial shutdown of the federal government.

When asked whether 2013 had been the worst year of his presidency, Obama laughed off the suggestion.

"We have had ups and we have had downs," Obama said. He added, jokingly, "I think this room has recorded at least 15 near-death experiences."

He said that despite the disastrous rollout of the online insurance exchanges at the heart of his signature health-care law, more than one million people have signed up for new health-care insurance since October.

Obama also noted that statistics released Friday showed the fastest economic growth in two years and said that this month's budget deal with Congress could be a sign of greater cooperation in Washington.

"It's probably too early to declare an outbreak of bipartisanship, but it's also fair to say that we are not condemned to endless gridlock," Obama said.