Seoul [South Korea], June 7 (ANI) Ahead of Chinese President Xi Jinping's state visit to North Korea, the powerful sister of Kim Jong-un has said her country's status as a nuclear-armed state is absolutely irreversible, calling it a 'line of no retreat' and vowing not to tolerate any threats against it 'The DPRK's status as a nuclear weapons state is the line of no retreat, and it is a stark reality whether anyon