Beijing (dpa) - China on Thursday condemned the auction of two Chinese bronze animal heads by Christie's and said it would impose restrictions on the firm's operations and exports of antiques from the country.

"In recent years, Christie's has frequently sold cultural heritage items looted or smuggled from China, and all items involved were illegally taken out of the country," the State Administration of Cultural Heritage (SACH) said.

The administration issued a notice to all exit-and-entry offices, which approve the export of antiques, saying they should "carefully check heritage items that Christie's seeks to import of export."

Christie's staff must provide "certificates of legal ownership" for all exported items, with detailed information on the history of ownership, the official Xinhua news agency quoted the notice as saying.

"Entry and exit departments should immediately report to the SACH and local police and customs offices if they find relics owned by Christie's that might have been looted or smuggled," it said.

The administration also issued a separate statement saying the auction of the heads had "damaged Chinese citizens' cultural rights and feelings and will have serious effects on Christie's development in China."

The statement accused Christie's of "violating international conventions" and the "common understanding" that such cultural relics should be returned to their country of origin, the agency said.

It followed the sale on Wednesday of the bronze rat and rabbit heads from the Yves Saint Laurent art collection for 14 million euros (17.84 million dollars) each.

The final bids far exceeded the estimate of 8 million to 10 million euros that Christie's had placed on them. Including buyers' fees, the price for the two bronzes totalled 31.5 million euros.

The Association for the Protection of Chinese Art in Europe and other Chinese groups had tried to prevent Christie's from selling the two bronzes because they were allegedly looted from China by British and French troops in 1860.

But a Paris judge ruled on Monday that there was no reason to withdraw the statues from the auction.

China's Foreign Affairs Ministry had also demanded the return of the two "precious cultural treasures which were looted by the joint Anglo-French forces."

"China has incontrovertible ownership of those objects, which should be returned to China," ministry spokeswomen Jiang Yu told reporters before the auction.

Saint Laurent's longtime partner, Pierre Berge, who helped organize the sale, said last week that he would return the bronzes to Chinese authorities only if they agreed to apply human rights and free Tibet.

The two bronze heads are believed to be part of a set of 12 representing the animals of the Chinese zodiac.

They were cast in the late 1750s and displayed at Beijing's Old Summer Palace, from where they were believed to have been looted in the razing of the palace by a British- and French-led force from eight foreign powers during the second Opium War. (dpa)