The arrests were carried out in raids in 19 towns and cities, most in the northeastern Barcelona province, according to a ministry statement. The arrested included 20 Spaniards and one Italian, according to the AP.
A police spokesman said he was unable to give details of the children's ages or the allegations against them. He said the three would be in the care of the children's attorney's office while the case against them is investigated.
Russian officials have repeatedly declared that Israeli aviation poses a threat to the Russian military in Syria.