He warned there could be more people missing.
At least 10 people died on the Spanish island of Mallorca after a torrential rainstorm caused flash flooding that left a trail of piled vehicles and damaged infrastructure from surges of water and mud.
MADRID-Torrential rainstorms caused flash flooding on the Spanish island of Mallorca, killing at least six people and leaving nine others missing on October 10, authorities said.
Spain's meteorological office said the neighbouring islands of Ibiza and Formentera were now on high alert as the rain and storms moved there.
The Foreign Office said it was "urgently seeking updates" from the authorities on the Spanish island, but would not confirm the deaths.
In Majorca, the worst affected area lay 60 kilometres (37 miles) east of the capital Palma de Majorca.
Swamped streets and piles of overturned cars, some of them along the guardrails of a major road, were a common sight in Sant Llorenc and other nearby towns on Wednesday.More news: Vaccinations Stressed as Flu Season Begins
At least three towns closed schools and hundreds of people were sheltered in sport facilities and a local horse racing track, authorities said.
The regional government called an emergency meeting, and authorities said rescue workers and military units had been sent to the area to help.
The Spanish Prime Minister Pedro Sánchez tweeted: "My solidarity and support goes out to the families and friends of victims and all those affected by these tragic floods".
Dramatic video footage on social media shows raging torrents of water gushing through the streets of the town, with reports that more than 20 centimetres of rain fell in just four hours.
The Spanish weather agency said more heavy rainfall is expected on Wednesday in eastern and southern parts of the Iberian peninsula.
The Spanish parliament held a tribute to the victims in the form of a minute's silence.