The response comes a day after a letter sent by Attorney General Jerry Brown said testing of the holiday toys revealed lead levels that violate federal law.
The products, which were made in China for Target's in-house brand, were identified as the retailer's two "Message Bears" - one a pink stuffed bear with "XOXO" across the chest and the other a brown stuffed bear with "I Love U" across the chest, with "love" represented by a heart.
Investigators from the Center for Environmental Health, a nonprofit watchdog, found that the bears' inflated vinyl letters contained well over federal limits for lead in products for children under the age of 12.
Beth Hanson, a spokeswoman for the Minneapolis-based Target, said the company received Brown's letter and has pulled the toys. She said it is conducting an internal investigation.
"We are removing the product from shelves as well as hard-locking them at the registers," Hanson said. "Target's initial investigation indicates this product had compliant testing results when it was shipped."
Hanson declined to say how many of the Valentine's Day bears Target had sold or purchased.
The lead levels were brought to Brown's attention by the center, which bought the toys at stores in California.
Lead exposure can damage the nervous system and other organs, and can be especially harmful to children.
"Parents need to know that lead-tainted vinyl has no place on products for their kids," Caroline Cox, research director for CEH, said in a statement.
The bears were sold exclusively by Target stores, the center's report stated.
"In this case, the laboratory identified lead levels nearly 10 times higher than those allowed under federal law," Brown's letter stated. "We ask that you stop selling the bears immediately and that you accept returns of the product, even without a receipt, as part of any corrective action."