ISTANBUL North Korea confirmed Thursday that it tested a hypersonic weapon the previous day, which was "clear proof” that it is steadily upgrading its self-defensive technical capabilities. The test, conducted by the country's missile administration, was overseen by high-level officials of the Central Committee of the Workers' Party of Korea (WPK), as well as the administration chief, according to the Korean Central News Agency (KCNA). South Korea's military said Wednesday that Pyongyang fired