(CNN)North Korea said it has hit the button on its fifth and potentially most powerful nuclear test Friday morning, claiming to have successfully detonated a nuclear warhead that could be mounted on ballistic rockets.

State media said the test would enable North Korea to produce "a variety of smaller, lighter and diversified nuclear warheads of higher strike power."

"It's hard for us to verify their claim. My deep fear is that they will launch a live nuclear weapon on one of their missiles, but that would be extremely dangerous as that could trigger a war," said Melissa Hanham, a senior research associate at the James Martin Center for Nonproliferation Studies.

World leaders condemned the test, saying it was a clear violation of UN Security Council resolutions, and the Security Council plans to hold an emergency meeting on the issue Friday.

President Barack Obama warned North Korea that it will face "consequences to its unlawful and dangerous actions."

He said he spoke to the leaders of South Korea and Japan by phone, and that all three agreed to "take additional significant steps, including new sanctions."

"To be clear, the United States does not, and never will, accept North Korea as a nuclear state," Obama said in a statement.

The blast, detected around 9 a.m. local time (8:30 p.m. ET), is estimated to have had the explosive power of 10 kilotons, almost twice as large as North Korea's most recent test in January, said Kim Nam-wook of South Korea's Meteorological Administration.

The test comes on North Korea's national day, and six months after it claim