A Tibetan exile with contacts in the region told Phayul.com, a Web site of Tibetan exiles in India, that one of the three Tibetans was feared dead and the other two survived.
Robert Barnett, director of the Tibetan studies program at Columbia University, told The New York Times there is much frustration in the Tibetan areas.
The three set themselves on fire in the southwest province of Sichuan to protest what their fellow Tibetans see as political and religious repression by Chinese authorities, the Times reported Sunday.
They are believed to be the first such drastic protests by Tibetans other than Buddhist monks, nuns or others associated with the clergy. Nineteen people have set themselves on fire in the past the past year.
"The three Tibetans called for the unity of the Tibetan people and protested against the Chinese government," the Tibetan exile said.
Tsering Woeser, a Tibetan poet in Beijing, said the three Tibetans in the latest incident had herded sheep and cows and were not members of the clergy, and that they lived far from the larger towns and monasteries where past protests had occurred.
The Times noted the current unrest is the largest since the 2008 protests in Tibet's capital of Lhasa.
There have been clashes lately with police in which Tibetans have reportedly died. The unrest has continued despite stepped up security by the Chinese government.
Barnett told the Times the incidents suggest such protests are spreading beyond the Tibetan clergy.
"There is a lot of frustration in the Tibetan areas," Barnett said. "People are saying they aren't being listened to; the government didn't respond constructively to the protests in 2008 and didn't respond constructively to the whole year we've seen of self-immolations."
Chinese authorities have blamed Tibetan separatists for the incidents.
The protesting Tibetans also have been demanding the return of the Dalai Lama and protesting China's occupation of Tibet.
The Dalai Lama, who has been living in exile in India since 1959 after a failed uprising in Tibet against Chinese rule, has been calling for more autonomy for Tibet than the current Chinese status of Tibet Autonomous Region.