Chinese police opened fire and wounded four protesters "in self-defence" last Sunday in a Tibetan area of Sichuan province, the Xinhua news agency says.
Tibetan activists say police killed protesters in Aba on Sunday
It is the first time China has admitted injuring anyone since anti-Chinese protests in Tibet began last week.
Xinhua said police opened fire in Aba county - the same place that Tibetan activists said eight people were killed during protests near Kirti monastery.
Activists released graphic photos of dead bodies showing bullet wounds.
China has said that only 13 people have been killed during the protests, and that all were innocent and killed by "rioters" in Lhasa.
The Tibetan government in exile has said at least 99 people have died so far, including 80 in Lhasa - and have accused the security forces of firing on crowds.
Earlier on Thursday, China admitted for the first time that the protests had spread outside the Tibetan Autonomous Region to nearby provinces in south-western China where large numbers of ethnic Tibetans live.
In a phone call to her Chinese counterpart, Yang Jiechi, US Secretary of State Condoleezza Rice urged China to show restraint and enter dialogue with the Dalai Lama, the exiled spiritual leader of Tibetan Buddhists.
Meanwhile White House spokeswoman Dana Perino said President George W Bush would go ahead with a visit to the Beijing Olympic Games in August despite the unrest, and would use the opportunity to speak openly to President Hu Jintao.
Citing police sources, Xinhua said police had opened fire "in self-defence" during Sunday's unrest in Aba, close to Sichuan's border with Qinghai province.
An earlier Xinhua report had said the police had shot dead four rioters, but it was quickly corrected.
The state-owned news agency had previously said only that "mobs" had caused "great damage" to shops and government offices in the area.
Xinhua did not provide further details of the incident, but Tibetan activists have said at least eight people were killed at a demonstration against Chinese rule near the Kirti monastery in Aba on Sunday.
The Tibetan Centre for Human Rights and Democracy circulated photos earlier this week of dead bodies with apparent gunshot wounds, which it said were the result of police firing indiscriminately at those attending the protest.
The group said many of the victims were monks who had joined thousands of others to demand independence for Tibet and the return of the Dalai Lama. Chinese police are deployed around the monastery to deter further protests, it said.
The BBC's China editor, Shirong Chen, says the situation in parts of western China is now extremely tense, with security being ratcheted up and many arrests.
Hundreds of troops have been seen pouring into Tibetan areas. On Wednesday alone, BBC reporters saw more than 400 troop carriers and other vehicles on the main road - the largest mobilisation witnessed since the unrest began.
The authorities have also placed strict limits on Western journalists trying to report on the unrest. A German journalist who was forced out of Lhasa on Thursday said security forces had told him he was the last foreign journalist in the city.
And officials said 24 people had been arrested after demonstrations in the Tibetan city of Lhasa, and 170 protesters had surrendered to authorities.
Earlier the Dalai Lama reiterated his willingness to meet Mr Hu if he received "concrete indications" of what the Chinese government can offer. But senior Chinese officials have repeatedly accused him of orchestrating the protests from his base in the Indian town of Dharamsala.