BEIJING -- China on Friday blasted a U.S. statement accusing Beijing of responding to a string of self-immolations by Tibetans with tightened controls over their freedom of religion, expression and assembly.

Maria Otero, a U.S. undersecretary of state and special co-ordinator for Tibetan Issues, said Wednesday that the U.S. government had consistently urged China to address policies in Tibetan areas, including "increasingly severe government controls" on Tibetan Buddhist religious practice, arbitrary detentions, and the use of force against Tibetans seeking to exercise their rights.

Her statement called on the Chinese government to allow Tibetans to express their grievances "without fear of retribution."

Foreign Ministry spokesman Hong Lei denied Otero's claims Friday and said that China had expressed its strong dissatisfaction to the U.S. over the statement, saying Washington should stop using Tibet to meddle in China's internal affairs.

"Tibetan people's rights to participate in political affairs, use the Tibetan language, maintain their traditional culture and religious freedom have all been duly protected like other people's in China," he said. "Tibetan people's freedom of expression and assembly and association are protected by the constitution."

Activists say at least 86 Tibetans have set themselves on fire since 2009 in dramatic protests against authoritarian Chinese rule. Tibet and surrounding ethnically Tibetan regions have been closed off to most outsiders, and firsthand information from the areas is extremely difficult to obtain.

Hong repeated China's position blaming the Tibetans' spiritual leader, the Dalai Lama, and his supporters for inciting the immolations and using it "as an opportunity to attack China's ethnic and religious policies."

"Inciting self-immolations is Dalai's way to realize his separatist political scheme," said Hong. "It's also the most cruel and inhumane criminal activity."

Hong said that in the past 30 years Tibetan areas had seen "leap frog development ... and a great improvement in human rights." He said Tibetans' political rights, language, religious freedom are fully protected.