The C-101 -- the same aircraft used by Spain's air force Eagle Patrol aerobatics team -- was on a training flight when it crashed near the resort of La Manga, the defence ministry said.

On board was a flight instructor who "was able to eject before the plane crashed in the sea".

But in a tweet, the air force said "everything indicates that our colleague... has died," saying "remains" had been found that needed to be examined by forensics.

A video filmed by a witness and posted on Twitter shows a small aircraft falling at a near vertical before trying to straighten up and hurtling into the water.

Emergency services said a search and rescue mission had been set up which includes the air force, navy, firefighters and coastguards.