Washington had earlier asked China to 'show restraint' and to talk to representatives of the Dalai Lama, Tibet's exiled spiritual leader.
China, however, claimed that the protests in Tibet were fomented by separatist agitators linked to the Dalai Lama.
Dalai Lama appeal
Meanwhile, Dalai Lama appealed from India on Wednesday for stronger international pressure on Beijing to halt its military crackdown in Tibet.
"Chinese authorities have deployed large contingents of troops in these traditional Tibetan regions and have not only started to crack down heavily on the Tibetans allegedly involved in the unrest, but also sealed off the areas where protests have taken place," the Tibetan leader said.
The Dalai Lama also said that many injured Tibetans were afraid to go to Chinese-run hospitals and clinics.
He urged for an international monitoring of the situation in Tibet.
"I would request you to encourage the sending of an independent international body, to investigate the unrest and its underlying causes, as well as allow the media and international medical teams to visit the affected areas."
He said, an international presence in Tibet will also exercise a restraining influence on the Chinese authorities.
Exiled Tibetan leaders have put the toll from the Chinese crackdown as 135 dead, 1,000 injured and many detained.
However, China has reported only a total of 20 deaths, 19 of which from Lhasa alone.