NEW YORK (Yonhap News) -- U.S. President Barack Obama warned Wednesday that North Korea will face "greater pressure and isolation" should it continue nuclear weapons development and

hostile actions against South Korea.

"North Korea has yet to take concrete steps toward abandoning its weapons, and continues belligerent actions against the South,"

Obama said in a speech at the opening of the United Nations General Assembly in New York.

He stressed, "if they continue down a path that is outside international law, they must be met with greater pressure and isolation. That is what our commitment to peace and security demands."

Obama, however, said North Koreans will see greater opportunity if their government abides by international rules and obligations.