ZURICH, Switzerland — Switzerland's watch industry exports fell nearly 10 percent in May as watchmakers continued to struggle with the aftermath of last year's extremist attacks in Europe and a prolonged slowdown in Asia.

Exports of timepieces fell 9.7 percent on a nominal basis to 1.55 billion Swiss francs ($1.61 billion), according to data released by the Swiss customs office on Tuesday.

The fall followed declines of 11.1 percent in April and 16.1 percent in March. Overall this year Swiss watch exports, which are seen as a proxy for sales, have fallen by 9.5 percent.

Particularly badly hit have been China and Hong Kong, two of the world's largest markets for luxury watches which are made by companies like Swatch, Richemont and LVMH Moet Hennessy Louis Vuitton .

Europe has also been struggling, with reduced tourism numbers in the wake of Islamist attacks last year reducing the number of visitors to important luxury shopping destinations like Paris.

Exports to France fell 18.4 percent in May, according to figures from the Federation of the Swiss Watch Industry.

In response, watchmakers have been cutting costs and production as the industry faces its biggest slowdown since 2009 when the global financial crisis reduced demand for luxury watches.

Last month, Geneva-based Richemont said it expected business to remain tough in the months ahead, as it reported a 1 percent fall in its constant sales for the 12 months ended March 31.

The owner of Cartier and IWC brands said April had been particularly difficult with sales down 15 percent in the month when currency swings were removed.

Difficulties in Richemont's watches business were exacerbated by inventories at retailers, which forced the company to buy back unsold watches.

No further job cuts were planned on top of the 500 cut last year, but more stores could close in China, Richemont said last month.

By John Revill; editor: Michael Shields.