Plans by North Korea to launch a satellite next month is \"a grave provocation,\" the South Korean prime minister said Tuesday. North Korea announced plans to deploy an Earth observation satellite using a long-range missile next month in a mission set to coincide with what would be the 100th birthday of former leader Kim Il Sung, grandfather of current leader Kim Jong Un. South Korean Prime Minister Kim Hwang-sik called for a heightened state of alert ahead of the planned mid-April launch. \"This is a grave provocation,\" he was quoted by South Korean\'s news agency Yonhap as saying. \"(We must) work closely with the international community to thoroughly examine and respond to the North\'s movements. We must maintain solid response readiness.\" North Korea announced this month that it placed a moratorium on long-range missile launches, nuclear tests and other nuclear-related material in exchange for food assistance from the United States. Seoul said it was anticipating talks with UN nuclear inspectors and North Korean officials.