US retailers see biggest-ever Cyber Monday after record online Black Friday

US retailers kicked off Cyber Monday by launching a slew of deals earlier than usual over the weekend, seeking to sustain the momentum of a record $11.6 billion in online sales on Thanksgiving and Black Friday.

Shoppers already had nearly a month of sales promotions as retailers look to draw out a holiday season that on paper is six days shorter this year due to a late Thanksgiving.

But estimates from Adobe Analytics on Sunday predicted the opening weekend of US retailers' crucial holiday season would set a new record of almost $30 billion in sales, with Cyber Monday - now traditionally the US economy's biggest online shopping day - alone expected to reach $9.4 billion.

Amazon.com Inc and other traditional retailers such as Target Corp and Walmart have beefed up delivery services to fulfill online orders faster as more customers order over their mobile phones and tablets from home.

This year, Target made free shipping available to all its customers throughout the shopping season, while Walmart offered shoppers the option of free two-day shipping or in-store pickup on the same day.

"The weekend between Black Friday and Cyber Monday is emerging as a truly lucrative period for online commerce," said Vivek Pandya, lead analyst at Adobe.

"Consumers ... are accelerating spend in the run-up to Cyber Monday."

A clear winner so far of the early deals and ramped up preparation for the holidays were retailers with greater online presence or those who had services such as "buy online and pick up at store".

The National Retail Federation estimates nearly 69 million Americans will scour the web for deals on everything from iPads and homeware to kids' toys, and Adobe's estimate of $9.4 billion would be a 19% increase on the same day a year ago.

Target on Black Friday announced that it would kick off a week of online discounts a day before, with new deals available every day until Dec. 9, while Kohl's Corp started online deals on Saturday, with deeper discounts on Monday.

Digital sales this year are also likely to get a big boost from orders through social media platforms like Youtube, WeChat, Instagram and Facebook.

"Brands and retailers will feel the effects of a Gen Z with even greater purchasing power," said Rob Graf, vice president of strategy and insights at industry software maker Salesforce.

"They are also pushing the boundaries of where actual purchases will happen."