Madrid - An earthquake struck southwest Spain and Portugal on Monday, measuring 6.3 on the Richter Scale.

The epicentre was in the sea off Cape San Vincente in Portugal but its effects were felt across south and central Spain.

The National Geographic Institute said the earthquake struck at about 11.35am.

A spokesman said it was the strongest earthquake to hit Andalusia for ten years.

Many parts of southern and central Spain felt the shock, including Marbella, Malaga, Guadalajara, Toledo, Albacete, Ciudad Real and Madrid.

The spokesman said as its centre was in the sea it should be treated as a small tsunami.

Hundreds of people left their homes and offices in Seville after feeling the shock.

Scores of calls were made to the emergency services from concerned people in Huelva.

But no injuries have been reported.