PORT HARCOURT, Nigeria (Reuters) - Dozens of doctors at a leading hospital in Nigeria's southern Edo state ended a four-day strike and returned to work on Saturday after a colleague was freed by kidnappers, the group's spokesman said.

More than 50 doctors from the main teaching hospital in Benin went on strike on Wednesday after unidentified gunmen abducted the chief medical doctor on his way home from work.

The doctors had demanded that authorities find the captors and bolster security in the area.

"The professor has regained freedom and is feeling well. With his release, we have called off the strike and since resumed work," said Dr. Osahon Enabulele, state chairman of the Nigeria Medical Association.

Kidnappings and other violent crimes are increasingly common, especially in the oil-producing Niger Delta. Most hostages are released unharmed after a ransom is paid.

It was not clear whether a ransom was paid for the doctor's release.

The four-day strike had forced the hospital to turn away new patients because nurses and interns were too overwhelmed in the doctors' absence.