U.S. President Barack Obama said Wednesday that North Korea's nuclear weapons program is one of the major challenges the U.S. is facing around the world, along with the Islamic State militant group.

Obama made the remark at a joint news conference with Argentine President Mauricio Macri during a visit to Buenos Aires, saying he's got many things done in his seven and a half years in office, but there still remain challenges to tackle.

Obama said the economy is much stronger now than when he came into office, and that his administration helped created 14 million new jobs and cut fiscal deficits by two thirds, and provided health insurance to 20 million people.

As foreign policy achievements, Obama put forward the normalization of relations with Cuba, the landmark nuclear deal with Iran, the end of war in Afghanistan and the democratic reforms in Mynamar.

"There's still major challenges. ISIL is still killing people. North Korea still has a nuclear weapons program. Middle East peace has not been achieved," Obama told the press conference after summit talks with the Argentine president.

"So, you know, if I were satisfied now, then I would be blind to the many challenges we face," he said.

After the North's fourth nuclear test in January, Republican members of Congress have slammed Obama's policy on North Korea, known as "strategic patience," as "strategic failure," pointing out that three of the North's four nuclear tests came while Obama was in office.

The Obama administration has been accused of ignoring the North's nuclear problem as it's preoccupied with Middle Eastern issues. (Yonhap)