North Korea fires short-range missile towards sea, says South

North Korea fired a short-range ballistic missile towards the Yellow Sea on Thursday, South Korea’s military reported, according to the Yonhap news agency.

In a statement, South Korea's Joint Chiefs of Staff (JCS) said that the launch was detected from the North's western port city of Nampo at 6.20pm.

The military did not immediately release an assessment on how far the missile flew.

“While strengthening its monitoring and vigilance, our military is maintaining a full readiness posture in close cooperation with the United States," the JCS statement said.

The development comes a day after North Korean leader Kim Jong-un’s sister Kim Yo-jong said the country was ready to take "quick, overwhelming action" in response to US and South Korean joint military drills.

“We keep our eye on the restless military moves by the U.S. forces and the South Korean puppet military and are always on standby to take appropriate, quick and overwhelming action at any time according to our judgment,” Ms Kim said in a statement featured on North Korea's state media.

The two militaries were training together in joint drills on Monday.

Training exercises included the use of B-52 bombers, which are capable of delivering a nuclear weapon, according to the Associated Press.

“The demonstrative military moves and all sorts of rhetoric by the U.S. and South Korea, which go so extremely frantic as not to be overlooked, undoubtedly provide (North Korea) with conditions for being forced to do something to cope with them,” Ms Kim added.