July 17 (Reuters) - Shoppers spent about $7.2 billion

online across retailers during the first day of Amazon's ( AMZN ) Prime

Day in the United States, according to a report from Adobe

Analytics on Wednesday.

Major retailers including Walmart ( WMT ) and Target ( TGT )

have launched deals and shopping events through July to attract

customers by offering deep discounts to compete with the Amazon ( AMZN )

sales event.

Adobe Analytics, which studies e-commerce transaction data,

had forecast that consumers could spend $7.1 billion online

across retailers on Tuesday, up 11.3% from a year earlier.