The streets of a town in eastern Spain were awash in red on Wednesday as revellers flung overripe tomatoes at each other in a high-spirited battle royale during the traditional Tomatina festival.

Some 22,000 participants wearing white clothes bespattered with tomato pulp engaged in the frenzy that grips Bunol - located 40 km (25 miles) to the west of Valencia - every year in the last week of August.

Seven trucks distributed 150 tons of ripe pear tomatoes to eager roisterers, many of them visiting from abroad. Non-residents pay a fee of 15 euros ($16.70), while Bunol locals enjoy it for free.

"We love tomatoes! That's why we decided to come and we had a fab time," said Taylor, who came from Australia, adding that she and her friends would "make some spaghetti to have with the sauce".

The start of the hour-long fight was signalled by firecrackers ignited once one of the contenders managed to climb up a slippery pole lathered in soap to snatch a leg of ham hanging from the top.

Senam, from Kenya, described the event as "beautiful, wonderful, creative, mind-blowing".

After the fracas ended, a cleaning crew armed with water hoses was dispatched to remove the refuse from the town's streets, which were left gleaming thanks to the tomatoes' natural acidity.

The fruits, grown specifically for the festival, are considered too sour for human consumption.

According to the Tomatina's official website, the festival originated during a brawl that ensued in 1945 when youngsters attempting to get a closer view of a parade knocked over one of the participants. Several people plucked tomatoes from a nearby stand as makeshift projectiles until police restored order.

The following year, youths recreated the altercation, with some even bringing their own tomatoes. The event was briefly outlawed in the 1950s under General Francisco Franco's fascist dictatorship, but resumed in 1959 with certain rules.