Danish shipping and energy group A.P. Moller-Maersk says an employee in Angola has been released unharmed, four days after he was abducted.

Group spokeswoman Louise Munter declined Tuesday in an email to The Associated Press to release further details, citing an "ongoing investigation by local authorities" and the security of its employees. The number of employees involved has not been disclosed.

She didn't say whether the man was an employee with its Maersk Oil division, the group's biggest activity in the African country.

According to the Copenhagen-based group, the off-shore, deep-water field Chissonga is the most important project in Angola which A.P. Moller-Maersk entered in 2005.