The US department of state has also warned black Americans that they risk attack by thugs who mistake them for west-African refugees or asylum-seekers because the US travellers may "appear to be members of racial minority groups".

Dublin is singled out for special mention in the latest official US government notice issued to Americans travelling abroad. The notice warns that robberies of small items from US citizens travelling in the capital, including "purse- and bag-snatching", have recently turned into violent incidents.

Americans travelling to well-known tourist areas in Ireland are targets for theft and violence, the notice highlights. "There is a high incidence of petty crime, mostly theft, burglary and purse-snatching in major tourist areas. Thieves target rental cars and tourists, particularly in the vicinity of tourists attractions, " the state department's written caution stated.

The new warning to US tourists was issued in recent weeks by the Bureau of Consular Affairs in Washington.

It is an updated version of the annual consular information which American tourists are advised to check before travelling abroad. The amended notice takes into account heightened concern of the US authorities about the risk of violence faced by their citizens when coming here to work or for pleasure.

US officials also warned prospective visitors to Ireland that they face the risk of being attacked by people opposed to the Bush administration's foreign policy, in particular its stance on Iraq and the Middle East. "Americans have reported incidents of verbal abuse and one reported a physical assault, apparently in reaction to US policy on the war on terrorism, " the circular noted. The state department advises US tourists to avoid public demonstrations and marches.

US tourists are also warned to beware of increased credit- and bank-card fraud here. "There has been an increase over the last year in the number of crimes involving credit cards and ATM cards. The use of skimmers to record credit-card details has increased [in Ireland] and these recorded details are being sent elsewhere to program false stolen cards."

Fine Gael spokesman on tourism, Jimmy Deenihan, said the warning by the US government highlighted the need for additional gardai on foot patrols in popular tourist areas, particularly during the summer months.

"The fact is that tourists have been robbed. We have to be aware of that. It is in the interests of the Irish tourism industry as a whole to acknowledge that and to deal with it.

"American tourists more than others have a tendency to come here and expect Ireland to be a place not unlike the country it was when their forefathers emigrated and that can leave them vulnerable. The best way to deal with this is to have enough gardai in the right places.

Unfortunately, the gardai are overstretched in this regard, " Deenihan said. "It is worth considering whether it would be effective to distribute information to travellers as they enter the country warning them that, while we are a safe country, they must be aware of certain risks, " he added.

"I recently came across someone who had come here for a golfing holiday and who had their golf clubs stolen.

A golfer will want to use their own clubs and while I was able to locate a replacement set of clubs, something like this can completely ruin a person's trip, " he said.

Tourism Ireland was not available for comment in relation to the US Department of State circular when contacted.