North and South Korea exchange gunfire at border

Tensions at the border as North Korean leader Kim Jong Un ended an almost three-week absence from public life. Photo / AP

North and South Korea have exchanged gunfire around the South's guard post, raising tensions a day after North Korean leader Kim Jong Un ended an almost three-week absence from public life.

Multiple gunshots were fired from North Korea at 7.41am local time towards a guard post in South Korea that borders the north, the South's joint chiefs of staffs said in a statement.

The Joint Chiefs of Staff in Seoul says North Korean troops fired several bullets at a South Korean guard post inside the heavily fortified border between the countries on Sunday.

South Korea responded by firing two shots towards North Korea.

No injuries were reported.

The gunfire was exchanged just hours after North Korean leader Kim Jong Un was seen publicly for the first time in weeks.

After weeks of intense speculation about Kim's health and whereabouts, the country's official media published photographs on Saturday showing Kim attending a ceremony for the completion of a fertiliser plant.

It was the first report of his appearance since April 11.

Some were suspicious of the images published by news agency Yonhap, with one sharp-eyed CNN correspondent noticing a detail in one of the recently-released photos that sparked controversy.

"He is conveniently framed below a banner with the date May 1. Let's see if they release video," CNN's Will Ripley shared on social media.

Media is tightly controlled in North Korea and it is often accused of spreading propaganda.