By Tom Housden BBC News Online

Spain's $50bn tourism industry has long been a target for Basque separatist group ETA.

In 2001 the authorities spent nearly $3m on improving security in tourist resorts after a series of bomb attacks, including attacks at a hotel in Salou and at Malaga airport.

It doesn't help things, but we have these bombings every year... we are used to them Juan Carlos Calvo, Merrill Lynch

One of the worst attacks came in 1997 when 35 British and Irish tourists were injured in an attack in Tarragona on the east coast.

But despite forecasts of a continuing slowdown in Spain's economy, analysts believe that business - and tourist confidence - will not be seriously affected by the latest bombs.

Merrill Lynch analyst Andrew Hunter told BBC News Online that it was too early to assess the immediate, or long-term impact.

"UK tour operators probably won't be hit, the result of this will probably be that people avoid Spain and go elsewhere. These bombings certainly aren't helpful, but at this moment they seem quite random and sporadic," Mr Hunter said.

'Outrageous attacks'

Association of British Travel Agents spokesman Sean Timpson said attacks on tourist targets were "absolutely outrageous".

"For business there is no positive effect. But there was a similar campaign last year, but we didn't see any significant drop in tourist numbers this year," he told BBC News Online.

Millions of Britons fly to Spain each year

"I think British tourists have a very realistic outlook on the dangers of terrorism," he added.

British tour operator First Choice said it was too early to predict any effect on business:

"Our priority at the moment is looking after our customers who are already out in Spain," a spokeswoman told BBC News Online.

The extent of the damage done to Spain's tourist industry may depend on the amount of media coverage the bombings get.

Spain's most popular tourist destinations - the Canary and Balearic islands - have never been targeted by ETA.

Tourism generates 9% of Spain's gross domestic product and employs 11% of the population. About 48 million foreign tourists visit Spain each year.