Seoul - North Korea fired several rockets into the sea on Saturday in the continuation of its rapid nuclear and missile expansion, while the United States and South Korea appeared to offer different readings of the success of the launches.The US Pacific Command said in a statement that three North Korean short-range missiles failed — two after flying an unspecified distance and another seemingly blowing up almost immediately. It added that the missile posed no threat to the US territory of Guam, which the North had previously warned it would fire missiles toward.South Korea's presidential office said North Korea presumably tested its 300-millimeter artillery rocket system. The county's military didn't mention any failures. It said the projectiles fired from the North's eastern coast flew about 250km.Kim Dong-yub, a former South Korean military official who is now an analyst at Seoul's Institute for Far Eastern Studies, said that South Korean assessments don't necessarily contradict the US evaluation that the launches involved ballistic missiles. While North Korea's large-sized artillery rockets blur the boundaries between artillery systems and ballistic missiles because they create their own thrust and are guided during delivery, Kim cautioned against writing off the launches purely as failures.The presidential office in Seoul said the US and South Korean militaries will proceed with their ongoing war games "even more thoroughly" in response to the launch.They are the first known missile firings since July, when the North successfully flight tested a pair of intercontinental ballistic missiles that analysts say could reach deep into the US mainland when perfected.The White House said that President Donald Trump — who has warned that he would unleash "fire and fury" if the North continued its threats — was briefed on the latest North Korean activity and "we are monitoring the situation.