Online giant Amazon has reported a 31% increase in first quarter sales to $4.39bn at its international division, which includes the UK.

Amazon’s net sales rose 38% year-on-year to $9.86bn at group level in the period to March 31. Net income fell 33% however to $201m, reflecting investment in the business.

Amazon founder and chief executive Jeff Bezos said: “In the last 90 days we announced Kindle with Special Offers, Kindle library lending, Audible audiobooks on Kindle, Appstore for Android, Amazon for Windows Phone 7, Checkout by Amazon in Germany and the UK, a Kindle store in Germany, Cloud Drive, Cloud Player and Prime Instant Video – just to call out a few of the things we’ve been working on.”