They were seized by armed groups in Libya in 2018.
According to the official news agency, WAM, the four engineers were abducted while working at a water desalination plant in western Libya, the UAE Foreign Ministry said in a statement.
”Upon receiving requests from the Philippines and South Korea, the UAE communicated with the Libyan National Army to work on releasing them and to ensure their safety,” the ministry said, referring to Libyan forces commanded by military strongman Khalifa Haftar.
The ministry said four were transported to the UAE capital Abu Dhabi prior to be taken to their home countries.
It was not immediately clear, who had abducted the four in Libya, or how they were released.
The UAE is considered an ally of Haftar whose forces have expanded their foothold in strife-wracked Libya in recent years.