China banned exports by two toy manufacturers whose products were subject to major recalls in the United States because they were decorated with lead-tainted paint, the government said Thursday.

The General Administration for Quality Supervision, Inspection and Quarantine said the restrictions on Lee Der Industrial Co. Ltd. and Hansheng Wood Products were temporary, but did not give any details.

"They have been asked to evaluate and change their business practices," the administration said in a notice on its website.

Mattel Inc. recalled 967,000 toys made by Lee Der last week because they were coated with paint found to have excessive amounts of lead. The plastic preschool toys, sold under the Fisher-Price brand in the U.S., included the popular Big Bird, Elmo, Dora and Diego characters.

The quality control watchdog also suggested that foreign companies who contract Chinese factories to make their products should take more responsibility.

"To prevent loopholes in quality control, overseas brand owners should improve their product design and supervision over product quality," the administration said.

The agency said police were investigating two companies' use of "fake plastic pigment" but did not elaborate. Such pigments are a type of industrial latex usually used to increase surface gloss and smoothness.

Chinese companies often have long supply chains, making it difficult to trace the exact origin of components, chemicals, and food additives.

Officials at Lee Der and Hansheng, both located in the southern province of Guangdong, said Thursday they had not heard about the export ban and refused to comment further.

It was not immediately clear how long the ban would last, or whether any further action was planned. The watchdog last month revoked the business licences of two other Chinese companies that made a tainted pet food ingredient blamed for causing the deaths of cats and dogs in North America.

The Chinese watchdog also warned that other toy manufacturers whose products do not meet safety standards overseas will not be allowed to sell their goods abroad until they rectify problems. But it said the majority of toys made in China were manufactured strictly according to foreign specifications.