North Korea launched three ballistic missiles toward the sea early Wednesday morning, South Korea’s military said. The missiles were launched off of North Korea’s eastern coast, according to a statement by South Korea’s Joint Chiefs of Staff, and came three days after American and South Korean leaders agreed to consider expanding military exercises in an effort to deter nuclear threats from the North. The launch marks North Korea’s 17th missile test this year, and experts say the testing aims to modernize the country’s weapons arsenal and put pressure on rivals. U.S. and South Korean officials have warned that North Korea could soon conduct its first nuclear test in almost five years. Kim Jong Un said last month that he is prepared to expand his country’s arsenal of nuclear forces “at the fastest possible speed.”