The source, at the National Emergency and Civil Protection Authority (ANEPC), said that the plane was located at 8.17 a.m. at a depth of 25 meters.

The FireBoss medium amphibious aircraft, which was serving the special team to combat rural fires, on Wednesday afternoon suffered "an accident when performing a manaeuvre of scooping” water from the River Zêzere, in the Trizio area.

"The alert went up at 4.46 p.m. and rescue teams were sent out, including a reconnaissance aircraft and a reconnaissance, evaluation and coordination helicopter at the service of ANEPC that immediately reconnoitered the site in order to identify the location of the accident," ANEPC said in a statement released on Wednesday that made clear that the pilot was unharmed.

The aircraft had been based at Proença-A-Nova, in Castelo Branco district, and was on its way to join the fight against a rural fire in the municipality of Ansião, in Leiria district.

The causes of the accident are to be determined by "entities with competence in the field of investigation of aircraft accidents", ANEPC said.

A source at the Office for the Prevention and Investigation of Aircraft and Railway Accidents (GPIAAF) told Lusa on Wednesday that it had been notified of the accident and would carry out an investigation.

According to a source at the National Institute of Medical Emergency (INEM), the pilot, 49, said he had no injuries and declined to be taken to hospital.