LISBON — A small plane crashed Monday beside a supermarket near Lisbon, killing four people on board the aircraft and one on the ground. Four people were slightly injured, emergency services said.

The dead included the Swiss pilot, three French passengers on the plane, and a Portuguese truck driver, said Miguel Cruz, emergency services operational commander.

The Swiss-registered plane crashed shortly after a noon takeoff from the small Tires airfield, 12 miles west of the Portuguese capital, Cruz said. Officials said the crash happened amid clear skies and a light wind.

The cause of the crash has not been determined.

Officials at the Tires airfield said the plane was a twin-engine Piper PA-31 Navajo aircraft. The airfield was closed as authorities opened an investigation.

The truck driver was ­off-loading his cargo at the supermarket’s rear cargo bay, about a mile from the runway, when the plane crashed near him. His truck was set ablaze.

Authorities declined to identify those killed in the plane until their identities could be compared with the flight plan.

The injured were shopping inside the supermarket and were treated for shock and smoke inhalation. The crash occurred about 150 yards from an elementary school.

About three dozen firefighting vehicles were sent to the scene, arriving within six minutes, according to officials. The fire was quickly brought under control.

Nearby houses were blackened by smoke, with nine people forced to evacuate their homes.

Portuguese President Marcelo Rebelo de Sousa traveled to the town after the accident to oversee the response of local authorities.

Associated Press