U.S. President Barack Obama said on Friday any provocative actions by North Korea would have "serious consequences" after the reclusive North confirmed it had conducted its fifth nuclear test.

Obama had been briefed on board Air Force One by National Security Adviser Susan Rice about reported seismic activity near North Korea's nuclear test site earlier on Friday, White House press secretary Josh Earnest said.

Obama reiterated the unbreakable U.S. commitment to the security of its allies in Asia and around the world, Earnest said.