Updated

An Argentine-born pilot for a low-cost airline was arrested during a stopover in a Spanish airport on suspicion of piloting planes that carried hundreds of dissidents to their deaths during his country's 1976-1983 "dirty war," authorities said Wednesday.

Julio Alberto Poch, a former Argentine navy lieutenant with Dutch nationality, is wanted in his native country on suspicion of piloting "death flights," during which drugged prisoners were thrown from airplanes and helicopters into the Atlantic Sea and Argentine rivers, Dutch foreign ministry spokesman Herbert Brinkman said.

He is wanted for questioning in four probes of more than 1,000 deaths during his time as a pilot at the Navy Mechanics School, a notorious torture center in Buenos Aires, Spanish police said

Spanish police said Poch was arrested Tuesday night after touching down at Valencia airport on a flight from the Netherlands. Police said they detained him during a 40-minute stopover before he was due to fly back Amsterdam.

The Dutch foreign ministry confirmed Poch was a pilot with Transavia, an airline that flies mainly tourist routes between the Netherlands and other European and North African cities.

Police said Poch frequently piloted planes to and from Schipol airport in Amsterdam to Maneses airport in Valencia, eastern Spain. They added that a replacement pilot had been arranged so that the flight could continue on its way after the arrest.

The Argentine government estimates about 13,000 died during the crackdown on dissent during the country's period of military rule between 1976-1983. Human rights groups say the toll is closer to 30,0000.