New Zealand scientists are monitoring the Pacific for radioactive fallout from North Korea's nuclear bomb test.
The country's third nuclear test was carried out on Tuesday and created an artificial magnitude 5.1 earthquake.
The Institute of Environmental Science and Research (ESR) believes the explosion was bigger than previous nuclear tests in 2006 and 2009.
It is contracted to provide monitoring at six stations, including in New Zealand and the Pacific, where it will look for radioactive gases and particles released by the test.
The sites in Kaitaia, Chatham Islands, Rarotonga, Fiji, Kiribati and Mauritania are part of a global network of stations managed by the Comprehensive Nuclear-Test-Ban Treaty Organization.
ESR says detecting isotopes released by the explosion will allow scientists to tell what type of bomb the North Koreans tested and help understand how advanced the country's nuclear programme is.
It is expecting only low levels of radiation because the bomb test was carried out underground, and does not expect there to be any danger to New Zealand.
The institute will combine its data with information from other monitoring stations around the world to help global understanding of the nuclear test.