Donald Trump’s successful campaign to become US president has claimed one of its first economic victims after luxury jeweller Tiffany blamed protests at Trump Tower for hitting sales at its flagship store.

Many of the demonstrations before and after the election have centred on the president-elect’s skyscraper in midtown Manhattan, located on the same block as the jewellery store on Fifth Avenue and 57th Street.

The site, described by the luxury goods company as “simply the most famous store there is”, is a tourist attraction almost as much as a retail outlet, mainly because of the enduring image of Audrey Hepburn’s alfresco dining and window shopping in the 1961 film Breakfast at Tiffany’s.

While sightseers have never appeared to scare away customers, political protesters might be viewed differently by Tiffany’s moneyed clients, at least according to a carefully worded results statement to Wall Street on Tuesday.

“With respect to the impact of recent election-related activity near the company’s New York flagship store, management has noted some adverse effect on traffic in that store and a continuation of sales softness relative to prior year and to the company’s other US stores this year,” the company said.

A protest outside Trump Tower on 12 November. Tiffany’s results do not cover the post-election period. Photograph: Kena Betancur/AFP/Getty Images

“That store represented less than 10% of worldwide net sales for the three and nine-month periods ended 31 October 2016, as well as for each quarter in fiscal 2015. The company cannot provide any assurance that sales in that store will not be negatively affected by this activity in the fourth quarter or in any future period.”

The results take in the three months to the end of October, so do not include the final days before the election, nor the 8 November result, which led to further protests at the site.

Tiffany said worldwide net sales rose by 1% to $949m (£761m) and comparable store sales fell by 2% over the period.

Its chief executive, Frederic Cumenal, remained cautious about the company’s prospects following a mixed year, with low bonuses for Wall Street bankers and weaker spending from foreign tourists.

“We are encouraged by some early signs of improvement in sales trends, but we clearly need more positive data over time before this can be considered an inflection point,” he said.