Amazon.com's Prime Day shopping event saw U.S. online sales rise nearly 6% to $6.4 billion from a year ago on its first day, as heavy discounts lured bargain-hunting customers who splurged on appliances and toys, Adobe Analytics data on Wednesday showed.

U.S. shoppers have been waiting for the best possible deals and discounts as rising interest rates and food prices have led them to delay purchases of big-ticket items in recent months.

Online sales for appliances jumped 37% on the first day, compared to average daily sales in June last year, while sales of toys rose 27%.

Adobe said shoppers can find the biggest discount of 16% on electronics on Wednesday.  Apparel is discounted at 13%, while toys were 15% cheaper.

To add more customers, Amazon has also partnered with travel booking site Priceline to offer discounts during the Prime Day as U.S. consumers prioritize experiences over non-essential spending.

In the weeks leading to Prime Day, members of the loyalty program were also given access to "invite-only deals" where shoppers could request invites to specific products that they were looking to purchase on deals.

Retailers, including Walmart, Target and Best Buy, also offered large discounts during the Prime Day week, competing with Amazon.

Back-to-school category also saw an increase in sales as parents looked to refresh wardrobes and school supplies for cheaper prices with apparel sales up 26% and electronics 12%.

A separate data by Deloitte showed 69% of shoppers planned to rely on Amazon's Prime Day sale for back-to-school purchases.

However, that spending is expected to decline for the first time in nine years as sticky inflation weighs on non-essential purchases, Deloitte said.

Adobe's data relies on direct consumer transactions based on more than 1 trillion visits to U.S. retail websites.

Meanwhile, nearly 900 Amazon workers at a warehouse in Coventry, in Britain are striking over a pay dispute for three days from July 11-13, coinciding with the Prime Day sales event.

Amazon said the site does not directly serve customer orders and there will be no disruption to customers.

(Reporting by Granth Vanaik and Ananya Mariam Rajesh in Bengaluru; Editing by Arun Koyyur)