 During the 7th Congress of the Workers' Party of Korea in 2016, Kim Jong-un stated that North Korea would "not use nuclear weapons first unless aggressive hostile forces use nuclear weapons to invade on our sovereignty".However, on other occasions, North Korea has threatened "pre-emptive" nuclear attacks against a US-led attack.In December 2015, Kim stated that his family "turned the DPRK into a powerful nuclear weapons state ready to detonate a self-reliant A-bomb and H-bomb to reliably defend its sovereignty and the dignity of the nation".