The latter were two British tourists who were in a taxi which was swept away by flood water.
The island was hit by devastating floods overnight, with torrential rainstorms hitting the town of Sant Lorrenc, about 40 miles east of the capital Palma.
Antonia Bauza, deputy mayor of Sant Llorenc des Cardassar, the worst-hit town, confirmed that two of the victims were British citizens. The driver was also killed.
Cars piled up after the flood..
Officials have said more than 600 rescuers and medical staff were at work and that emergency relief centres had been set up in sports halls.
Local television showed footage of beach umbrellas floating in the sea near S'Illot, one of the affected coastal villages, one man looking at the water with his binoculars to spot any missing people.
"It all happened in less than 10 minutes", an unidentified witness with wet clothes and a blanket over his shoulders told TVE.
Image Heavy rain and flash floods hit Sant Llorenc de Cardassar on the island of Mallorca Spain
Others were caught on the road, unable to reach their houses. In all, more than 500 people helped with rescue and cleaning up operations, authorities said. When she finally made it home on Wednesday, all she found was chaos.
"We are grateful that we are all alive, but we pray for those that have lost their lives to this huge flood", Oliver said.
A sports centre - the Miguel Ángel Nadal sports centre in the town of Manacor - has opened its doors to give shelter to local people whose homes have been damaged. The flooding also affected phone communications and forced the closure of at least seven major roads.
"This is hardly seen in the islands", Del Campo said.
"In just two hours, some 180 litres of rain fell and we realized that we could not control the water", she said.
The Spanish weather agency said more heavy rainfall is expected on Wednesday in eastern and southern parts of the Iberian peninsula.
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