North Korea launched another ballistic missile Tuesday, just a few days after the leaders of South Korea and the United States agreed to leave the door open for dialogue with the communist nation.

"North Korea fired an unidentified ballistic missile into the East Sea from the vicinity of Banghyon, North Pyongan Province, at around 9:40 a.m.," the Joint Chiefs of Staff (JCS) said.

The North's provocation was immediately reported to President Moon Jae-in, it added, as Moon ordered the National Security Council to convene an emergency session.

Army Col. Roh Jae-cheon, a spokesman for the JCS, told reporters that the missile traveled "several hundreds of kilometers," which means the firing was successful.

"But South Korea and the U.S. are analyzing the apogee of the missile and its exact flight distance," he added. "Our military is maintaining full preparedness against the possibility of North Korea's additional provocation."

A government source said the missile is estimated to have flown 800-900 km.

Japanese media reported that the missile may have landed in Japan's exclusive economic zone (EEZ).

In talks with Moon in Washington, D.C. last week, U.S. President Donald Trump expressed support for the South Korean president's push for improving inter-Korean relations.

The North fired four surface-to-ship cruise missiles on June 8 in the wake of a ballistic missile launch about a week earlier.

The latest launch came as the South's president plans to leave for Germany to attend the Group of 20 summit, where he is scheduled to hold a trilateral meeting with Trump and Japan's Prime Minister Shinzo Abe.

North Korea is apparently diversifying its missile inventory and launch sites as well in order to hide its testing until the last minute. (Yonhap)