Shoppers purchase electronics and other items at a Best Buy in San Diego, California.

Foot traffic at retailers across the country this holiday weekend may not have been as strong this year when compared to last, a retail tracking firm said on Saturday, despite effusive early results from some retailers.

Preliminary data tracking shoppers' visits to physical stores on Thanksgiving Day and Black Friday shows a year-over-year decline of 1.6 percent, ShopperTrak said. Meanwhile, store visits solely on Black Friday dropped less than 1 percent compared with 2016, essentially remaining unchanged.

However, ShopperTrak's data doesn't necessarily mean overall holiday sales were weaker. Separate figures suggested that, rather than going into brick-and-mortar stores, an increasing number of consumers turned to their mobile phones during the entire month of November to shop for deals.

"There has been a significant amount of debate surrounding the shifting importance of brick-and-mortar retail, and the fact that shopper visits remained intact on Black Friday illustrates that physical retail is still highly relevant and, when done right, profitable," Brian Field, senior director of advisory services for ShopperTrak, said in a statement.

The early traffic results imply that online buying continues to take a larger share of shoppers' dollars during the holidays.

Though many retailers have boasted long lines at stores this year, the growth looks muted at best. Meantime, more companies are pushing discounts earlier in the month, and promoting Black Friday sales simultaneously via the Web.

"We know that opening on Thanksgiving Day was merely pulling shopping visits from Black Friday, as opposed to creating an additional opportunity for shoppers to hit the stores," Field said about that strategy.

Adobe Insights, which measures 80 percent of digital spending from 100 major U.S. retailers, said a record $5.03 billion was spent online by the end of Black Friday, an increase of 17 percent from a year ago.

Purchases made on mobile devices accounted for nearly 37 percent of total revenue that day, Adobe found.

Despite brisk Internet sales, ShopperTrak said the season isn't over for physical retail just yet, with eight of 10 anticipated "busiest shopping days" still left to go. That includes Dec. 23 and Dec. 16.

ShopperTrak will share additional insights regarding Black Friday this upcoming week.