China has rejected international criticism over the deportation of a group of Tibetans from Nepal.
By Sushil Sharma
BBC correspondent in Kathmandu
The Chinese embassy in the kingdom's capital, Kathmandu, said that their deportation was legal as they were illegal immigrants.
Critics however called the move a blatant violation of international law.
This action... tarnishes
Nepal's longstanding and well-deserved reputation for tolerance and
A statement from the Chinese embassy said the deported Tibetans were not refugees.
It said that they were Chinese nationals who had violated the immigration laws of Nepal and China.
Beijing says Tibet has been part of China for centuries. Chinese troops occupied Tibet in 1950.
The Chinese reaction came in response to criticism from the United States, the United Kingdom and the United Nations High Commissioner for Refugees (UNHCR).
Many Tibetans flee to India, where the Dalai Lama lives in exile
The UNHCR called the deportations a blatant violation of Nepal's obligations under international law.
It said the deportations represented a major shift in Nepal's policy.
The Nepalese authorities denied that there has been such a shift.
The 18 Tibetans, including eight minors, were deported to China last Saturday, almost two months after they had been arrested on charges of illegally entering the country.
Every year, hundreds of Tibetans cross over to Nepal on their way to Dharamsala in India, where their spiritual leader, the Dalai Lama, has been living since he fled Tibet more than 40 ago.
The Tibetans are normally kept in a transit camp in Kathmandu pending interviews with the UNHCR, which facilitates their travel to India.
People with criminal records are deported to China.
Good relations crucial
The UNHCR said the Nepalese authorities had refused them access to the arrested Tibetans and rejected their plea against the deportations.
There had been persistent speculation that Chinese pressure influenced the move.
Maintaining good relations with its mighty northern neighbour is crucial for Nepal.
About 20,000 Tibetans have been living in Nepal for the past 40 years. They are not allowed to undertake political activities.