Spanish investigators are continuing their search for meteorite fragments following spectacular sightings of fireballs in the sky on Sunday.
Fields near Leon were charred by the mysterious fireballs
Police combed a number of areas on Monday - concentrating on an area near Leon and Palencia - but have found nothing so far.
They received hundreds of calls at the weekend about loud explosions, tremors and colourful displays in the sky.
Experts say the cause may have been a disintegrating meteoroid.
However, they say the noise and tremors may have been caused by it breaking the sound barrier rather than crashing into the ground.
Police sources believe the meteoroid broke up over the northern parts of Leon and Palencia, where civil guard officers reported seeing an object plunging from the skies.
But they say the parts may have fallen over as many as seven regions, in an arc running from the north-west to the south-east of Spain.
Around 100 police and members of civil protection took part in searches on Monday in Leon, Palencia, Cuenca and Soria regions, according to El Periodico newspaper.
Spanish TV showed pictures of charred vegetation and six holes, about 30 centimetres in diameter, near Minglanilla in the eastern Cuenca Province.
But experts from the Superior Council for Scientific Investigations said later that these craters had no relation to a meteorite.
Jose Angel Docobo, director of the University of Santiago's observatory, believes that the largest of the fragments fell near the town of Molina de Aragon, near Guadalajara, 54 kilometres north of Madrid.
Mr Docobo, who witnessed the spectacle during a soccer match, says the fragments could be strewn over a radius of 100 kilometres.
He estimated that the meteoroid weighed between 50 and 100 tonnes.
His observatory carried out a study eight years ago on a similar incident when a meteoroid weighing an estimated 10 tonnes dropped debris over Spain.
A meteorite also fell to Earth in Spain near Reliegos in Leon province in autumn 1947.