China on Thursday successfully conducted a land-based mid-course missile interception test, said the Ministry of National Defense.

The test was for defensive purposes and not targeted at any country, the ministry said in a statement.

The test on Thursday was the fifth land-based anti-ballistic missile (ABM) technical test China has publicly announced and the fourth land-based mid-course ABM technical test publicly known. 

Past ABM tests were carried out in 2010, 2013, 2014 and 2018 respectively, according to media reports and official statements. 

The flight of a ballistic missile usually consists of three phases in time order: boost phase in which the rocket booster will power the missile into sky, mid-course phase in which the booster stops as the missile traverses outside of the atmosphere, and reentry or terminal phase in which the missile reenters the atmosphere and dives onto its target.

It's technically easy to intercept a ballistic missile in the boost phase, because the missile is still close to the ground and accelerating, but it is difficult to get close to the launch site which is usually deep in hostile territory; in terminal phase, the interception is challenging because the speed of the diving missile is very high, observers said.

Mid-course is the most vital phase in the interception of a ballistic missile, and a mid-course ABM means intercepting the missile while it is in its free flight phase outside of the atmosphere, Song Zhongping, a Chinese military expert and TV commentator, told the Global Times.

One of the biggest difficulties of an interception lies in the high trajectory as the duration of the mid-course phase is relatively long, Song said, noting that the target of interception is usually an intermediate-range or intercontinental ballistic missile.

The latest test shows that China's ABM system is becoming mature with the success rate and reliability of interceptions increasing significantly, which is very important for China to build a complete ABM system, Song said.