Palestinian medical officials say an off-duty security officer has been shot dead in an exchange of fire at the border crossing between Gaza and Egypt.
Several others were injured in the incident at the Rafah crossing.
Witnesses said the shooting started after Palestinian officers tried to stop at least one man barging his way through controls at the crossing.
The border crossing at Rafah, in southern Gaza, has been closed for large periods over the past year.
When it opens it is often swamped with large numbers of people wanting to pass through in both directions.