South Korea successfully test-fired its new ballistic missile capable of striking all parts of North Korea last month and plans to deploy it starting next year to bolster its defense, a military source said Friday. The state-funded Agency for Defense Development (ADD) on March 23 tested the ballistic missile with a range of 500 kilometers and a payload of 1 ton at a firing range in Taean, South Chungcheong Province, which was observed by senior military officials. "The missiles accurately hit the intended target," the official said, asking for anonymity. South Korea currently operates 300-km Hyunmoo ballistic missiles, and has been developing longer range missiles to beef up its defense against Pyongyang under a new missile deal with the United States. The guideline revised in October 2012 allows Seoul to extend the maximum range of its ballistic missiles from 300 km to 800 km. It limits the maximum payload to 500 kg for 800-km range missiles, while allowing heavier payloads for missiles with shorter ranges. Following the deployment of the 500-km range missile, the military plans to develop an 800-km missile with a payload of 500 kg and test-fire it next year, the official said. The latest move comes in response to rising risks from the communist rival, which has fired short-range rockets and missiles as well as mid-range missiles in the past few weeks in response to the ongoing joint military exercise between Seoul and Washington. Pyongyang has deployed various ranges of ballistic missiles, which are capable of striking South Korea, Japan and U.S. Pacific bases, while developing intercontinental ballistic missiles (ICBMs). Seoul officials believe the North has not yet mastered the technology to produce a nuclear-tipped ICBM capable of hitting the U.S. mainland.