It is only two days until the Black Friday shopping blitz.

Toys will be among the most popular items this holiday season. But consumer groups are warning the public that some items purchased off online marketplaces may miss the mark on safety.

The groups say buyers should watch for e-commerce listings that don’t disclose a manufacturer or ship from overseas, as they may not comply with United States safety standards.

Customers should also do their own research before buying anything online.

"Negative reviews should be a yellow to red flag, especially if there are a lot of them,” says Oriene Shin, Consumer Reports manager for Safety Advocacy. “Then check the federal government's website for recall warnings or any useful safety information."

Consumers should also check to see if a product is being sold on major retail websites.