An apartment fire in Barcelona left the young siblings dead on Monday morning as emergency services are still investigating the cause of the blaze, local newspaper La Vanguardia reported.
Their two-year-old brother was fighting for his life after being pulled from the flames at the apartment block in the Sant Martí district of the Catalan capital.
The fire began at about 9am within a ground floor flat where the three children lived with their mother. The youngest sibling and mother were both badly burned and around 11 other people also suffered injuries due to the fire.
Some residents of the building were injured when they attempted to escape the flames, including some Chinese tourists who had jumped from a balcony to get away.
Barcelona fire services reported on Twitter by noon that the fire had been extinguished.
Incendi extingit C/ Rodes 4-6. 2 menors de menys de 10 anys morts, 1 menor de menys de 10 hospitalitzat i 11 ferits de diversa consideració.
— Bombers Barcelona (@BCN_Bombers) July 11, 2016
The area around the building has been blocked off as rescue workers brought the most seriously injured to hospital.
Note: Earlier is was reported that the third sibling was a little girl. Spanish media now report that it was a two-year-old boy.