Here is the full text of the English-language statement by North Korea's official Korean Central News Agency, announcing Tuesday's nuclear test.
The Democratic People's Republic of Korea (DPRK) is the North's official name. The Korean-language version of the statement referred to a "miniaturised" bomb, while the English text termed it a "smaller" device:
"The scientific field for national defence of the DPRK succeeded in the third underground nuclear test at the site for underground nuclear test in the northern part of the DPRK on Tuesday. The test was carried out as part of practical measures of counteraction to defend the country's security and sovereignty in the face of the ferocious hostile act of the U.S. which wantonly violated the DPRK's legitimate right to launch satellite for peaceful purposes.
"The test was conducted in a safe and perfect way on a high level with the use of a smaller and light A-bomb unlike the previous ones, yet with great explosive power.
"It was confirmed that the test did not give any adverse effect to the surrounding ecological environment. The specific features of the function and explosive power of the A-bomb and all other measurements fully tallied with the values of the design, physically demonstrating the good performance of the DPRK's nuclear deterrence that has become diversified.
"The nuclear test will greatly encourage the army and people of the DPRK in their efforts to build a thriving nation with the same spirit and mettle as displayed in conquering space, and offer an important occasion in ensuring peace and stability in the Korean Peninsula and the region."