A North Korean doctor and his wife were kidnapped by Islamic State (Isis) militants in Sirte last week while they were on their way to Tripoli, The Korean Times reported, citing the Libya Observer.

The doctor, 60, has been working at a hospital in Libya for six years, the report said.

The motive behind kidnapping the North Koreans is still not clear. The couple's driver, who was also kidnapped with them, has been released.

Isis is known to kidnap nationals of different countries to demand ransom from governments.

There are about 400 North Koreans living in Libya, the paper reported.

The North Korean embassy is reportedly working to ascertain the couple's location.