According to Adobe Digital Index, US consumers spent $1.15 billion (1.08 billion euros) between midnight and 5pm Eastern Time on Thursday on online sales that were 14 percent higher than a year ago.

"Online discounts are earlier and a lot bigger than last year," said Tamara Gaffney, principal research analyst at Adobe Digital Index.

Online shopping on Thanksgiving has gained in popularity, with e-commerce retailers like Amazon, Alibaba and others offering cheap deals.

"We saw one of our strongest days ever online," Brian Cornell, chief executive of discount retailer Target, told reporters on Thursday evening. He added that online sales grew by double digits, without giving further details.

Make-or-break for retailers

Traditionally the day after Thanksgiving, also known as Black Friday, has started the holiday shopping season in the United States with retailers offering steep discounts.

"Black Friday is no longer a one-day event; it has turned into a multi-week event," Christopher Baldwin, chief executive officer at BJ's Wholesale Club, told the news agency Reuters.

The holiday season spanning November and December is crucial for retailers because it can account for as much as 40 percent of annual sales. Retailers try to attract shoppers with deep discounts, sometimes as much as 85 percent.

The National Retail Federation expects holiday sales to grow 3.6 percent this year to $655.8 billion.

uhe/jd (Reuters, AFP)