In February 2017, following the alleged state-sponsored murder of Kim Jong-nam (Supreme Leader Kim Jong-un's half-brother) using the nerve agent VX (banned under the international Chemical Weapons Convention, a convention which the North Korean government has not signed), pressure was placed on the Trump administration to revoke Bush's lifting of sanctions. In April 2017, US Congress backed a bill to reinstate North Korea as a state sponsor of terror following the 2017 Shayrat missile strike in Syria, which North Korea had condemned vehemently. In August of the same year, the nation launched a missile that flew over Hokkaido, Japan, promoting severe condemnation from other states. In September, the parents of Otto Warmbier, who had died after being imprisoned in the nation, stated that they want North Korea to be relisted for his apparent murder.