Kerry: U.S. will not accept North Korea as a nuclear state

U.S. Secretary of State John Kerry said on Tuesday that the U.S. would not accept North Korea as a nuclear state.

Kerry's warning came only hours after Pyongyang announced that it will restart a nuclear reactor that has been dormant for five years, CNN reports.

The decision to resume activity at the nuclear reactor comes at a time when North Korea has raised tensions with South Korea and the United States.

"The bottom line is simply that what Kim Jong Un is choosing to do is provocative," Kerry said, according to CNN. "It is dangerous, reckless. The United States will not accept the DPRK (Democratic People's Republic of Korea) as a nuclear state.

"And I reiterate again the United States will do what is necessary to defend ourselves and defend our allies, Korea and Japan. We are fully prepared and capable of doing so, and I think the DPRK understands that."

The re-opening of the reactor is seen by experts as a demonstration by Kim of the country's nuclear weapons program, which the international community has repeatedly attempted to get the country to abandon.

The facility includes a uranium enrichment facility and a reactor that was disabled following an October 2007 agreement between North Korea, the U.S. and four other nations, CNN reports.