NEW YORK (Reuters) - Two leaders of the U.S. Consumer Products Safety Commission are calling for the agency to investigate e-commerce retailers Shein and Temu after "deadly baby and toddler products" were sold on both websites, according to a letter posted on the agency's website on Tuesday.

CPSC Commissioners Peter Feldman and Douglas Dziak want the agency to evaluate how Singapore's Shein, China's Temu and other foreign-owned e-commerce platforms comply with its rules, handle relationships with third-party sellers and represent imported products.

Shein and PDD Group's Temu, which both ship cheap merchandise into the U.S. from China, are raising "specific concerns" for the Commission for their use of de minimis, a rule exempting packages valued at $800 or less from tariffs if they are sent directly to shoppers.

A Shein spokesperson said the company is investing millions of dollars into strengthening its compliance programs. Earlier this year, Shein announced it would pour $50 million into compliance programs to ensure strict adherence to product safety standards and local laws and regulations.

Temu will cooperate any U.S. CPSC investigation, a company spokesperson said. The e-retailer requires all sellers to comply with applicable laws and regulations, including those related to product safety, the spokesperson said.

Critics of Shein and Temu attribute low prices and de minimis to Shein and Temu's success in the U.S. Both companies have also come under scrutiny for the quality of their products.

A bipartisan group of U.S. lawmakers last year planned to introduce a bill to eliminate the de minimis rule, which is widely used by e-commerce platforms, including third-party sellers on Amazon.com and Walmart.com.