North Korea has fired three ballistic missiles into the Sea of Japan, say US and South Korean military officials.The missiles were launched from the western city of Hwangju, said South Korea’s Joint Chiefs of Staff.The US said the first two were believed to be short-range Scud missiles while the third was presumed to be a mid-range Rodong, reports BBC.It comes after the US and South Korea said they would deploy an anti-missile system to counter the North’s threats.North Korea is barred by UN sanctions from any test of nuclear or ballistic missile technology. But tensions have soared since it carried out its fourth nuclear test in January.It has also conducted several launches in recent months, including a test of mid-range missiles in June which were considered it’s most successful yet. Seoul has said activity detected recently in North Korea indicates it could be preparing to conduct a fifth nuclear test imminently.The latest launches happened between 05:45 local time (20:45 GMT on Monday) and 06:40, the South’s military said, in a statement quoted by Yonhap news agency.‘The ballistic missiles flight went from 500km (310 miles) to 600km, which is a distance far enough to strike all of South Korea including Busan,’ South Korea’s military said in a statement. Busan is a port city in the south.The US Strategic Command said it had tracked the launches, but that they had posed no risk to US interests.Earlier this month, Seoul and Washington agreed to deploy the Terminal High Altitude Area Defence (THAAD) anti-missile system in the South. The system will be based in the town of Seongju, in the south-east.The North’s military had warned it would retaliate with a ‘physical response’. China has also criticized the decision, saying it will destabilize security in the region.