US Secretary of State John Kerry and UN Secretary General Ban Ki-moon on Thursday urged strong international steps in response to the North Korean nuclear test earlier this week, dpa reports.
"With respect to North Korea, this week's test was an enormously provocative act that warrants a strong, a swift, and a credible response from the global community," Kerry said ahead of talks with Ban at the State Department.
"In the days ahead, Mr Secretary General, we're going to ramp up our coordination with the Six-Party partners, with the Security Council and other UN members, and other allies and partners in order to guarantee that we respond appropriately."
Ban called the test "a direct challenge to the international community" and called on Pyongyang to end its nuclear programme.
"I encourage the Security Council to act with unity and to take appropriate measures as soon as possible," he said.
Pyongyang on Tuesday carried out an underground test of its most powerful nuclear device to date, saying it was in response to recent sanctions.