A US F-16 fighter jet dropped two of its fuel tanks into waters off South Korea's west coast as it experienced an "in-flight emergency" before safely returning to base, a US Air Force unit said.

The F-16 of the 8th Fighter Wing jettisoned the tanks into the Yellow Sea as it experienced the emergency at about 10 a.m. after taking off for a routine sortie from Kunsan Air Base in Gunsan, 178 kilometers south of Seoul, according to the unit.

The pilot still managed to return safely to base, it said, noting an investigation will take place into the cause of the emergency situation.

The latest incident came after a US F-16 crashed in waters off Gunsan last month, which marked the third US aircraft crash of its kind in South Korea in a year.

In December, an F-16 crashed into the Yellow Sea during routine training, while another F-16 crashed near Osan Air Base in Pyeongtaek, 60 kilometers south of Seoul, in May.

There were no casualties in all three crashes as the pilots ejected from the aircraft.