The Democratic People's Republic of Korea (DPRK) announced Friday that that it has carried out a nuclear warhead explosion, according to state-run television. It is the country's fifth nuclear test. The following is a review of the country's previous nuclear tests.

Oct. 9, 2006 -- The official KCNA news agency reports that the DPRK conducted a successful nuclear test in North Hamgyong province in the country's northeast. The UN Security Council on Oct. 14 passes Resolution 1718 to condemn the test.

May 25, 2009 -- The DPRK conducts its second nuclear test. The KCNA says that DPRK scientists have been able to increase the explosive power and control level of the bomb compared with the first test.

The test prompts UN Security Council Resolution 1874, which voices "the strongest condemnation" against DPRK authorities and demands the country stop further nuclear weapons-related activities.

Feb. 12, 2013 -- The DPRK carries out a third nuclear test, which the KCNA describes as "high level, safe and perfect."

South Korea estimates the bomb has a power equal to 6,000-7,000 tons of TNT. The UN Security Council unanimously passes Resolution 2094 on March 7, demanding the DPRK give up its nuclear weapons project and return to the Nuclear Non-Proliferation Treaty.

Jan. 6, 2016 -- The DPRK carried out its fourth nuclear test, alleged to be a successful test of its first hydrogen bomb. The test means that the DPRK has "proudly joined the advanced ranks of nuclear weapons states possessing the H-bomb," said the state news agency KCNA.