The retailer said group profit before tax for the 13 weeks to April 30 rose to£27.9 million, compared with£26.1 million for the same period last year.
US stores operating profit was up from£27.1 million the first quarter last year to£31.4 million. Like-for-like sales rose by 7.1 per cent against strong comparatives.
Contrasting the impressive figures in the US, trading in the UK has suffered from the general consumer gloom. Like-for-like sales fell by 6.4 per cent and 6 per cent respectively at H Samuel and Ernest Jones over the period. As a whole, the division made an operating loss of£400,000.
Signet group chief executive Terry Burman said: 'We are very pleased with the increase in Group earnings of 10 per cent, given the present challenging trading conditions in the UK. The general retail environment in the UK remained very difficult throughout the quarter. We are continuing to adhere to our proven strategy, although we will ensure that costs, gross margins and cash flow remain tightly managed.'