Almost six million water bottles from a popular brand marketed for children were recalled Tuesday because they might present a choking hazard.

Contigo, a North Carolina manufacturer, announced the recall Tuesday of about 5.7 million of its Kids Cleanable Water Bottles because the black spout on top could come off and potentially choke a young user, the U.S. Consumer Product Safety Commission said.

5.7 million kids water bottles sold at Target, Walmart recalled for choking hazard https://t.co/SWNfCzqjnb — WXII 12 News (@WXII) August 27, 2019

These bottles came in sizes of 13, 14 and 20 ounces, authorities said.

The announcement comes as millions of children head back to school.

"Contigo has received 149 reports of the spout detaching, including 18 spouts found in children’s mouths," the commission said.

The bottles were sold at Costco, Walmart, Target, other stores nationwide and online on various websites from April 2018 through June 2019. They sold for between $9 and $24 each, federal officials said.

"Out of an abundance of caution, we encourage consumers to find out if they have an affected water bottle lid and order a free replacement lid, " the company said in a statement. "We sincerely apologize for any inconvenience."

Contigo said it would mail a replacement spout for any that is defective.