Thousands of cheering revellers sprayed wine at each other as the El Chupinazo firecracker was launched in Pamplona to kick off the 'San Fermin' nine-day annual bull-running festival.

Crowds of Spaniards and foreign visitors packed the town square dressed in the festival's traditional white t-shirts and trousers while holding up red handkerchiefs for a noisy and colourful party.

The Chupinazo marks the beginning of 204 hours of uninterrupted party until the 14th of July at midnight.

Seconds after the firecracker was launched the delighted crowd tied their red handkerchiefs around their necks.

Thousands of people drenched each other with wine, flour and champagne while throwing around inflatable balls, singing and dancing.

During the runs, which start each morning at 8 am, thousands of people run chased by fighting bulls along a route through the town's narrow streets from a corral to the city bullring.

"Los San Fermines" are considered Spain's most famous fiesta and were popularized internationally by Ernest Hemingway's 1926 novel "The Sun Also Rises."