Romanian authorities have mobilized more than 1,000 rescuers in a massive search operation for a missing pilot and his glider now in its fifth day.

Mircea Craciun, one of Romania's most experienced gliders, went missing on Thursday after taking off on a private flight from the town of Ghimbav in mountainous central Romania.

The disappearance of the 57-year-old pilot has prompted a massive search and rescue effort.

By Monday, authorities had mobilized 1,350 rescue workers, 11 planes, choppers and drones and some 220 ground vehicles.

The Interior Ministry said Monday the search would be extended to hard-to-access areas of three counties in central Romania.