Beijing - Two Tibetans were put to death after being convicted in deadly arsons during rioting in Lhasa one and a half years ago, the first executions to be officially confirmed from the violence, a Tibet advocacy group said Tuesday.

The Chinese embassy in London confirmed the executions to the British Foreign Office, the Washington-based International Campaign for Tibet said.

A spokesman for the office in London condemned the executions.

"We respect China's right to bring those responsible for the violence in Tibet last year to justice, but the UK opposes the death penalty in all circumstances, and we have consistently raised our concerns about lack of due process in these cases in particular," he said.

A spokesman for China's Foreign Affairs Ministry, Ma Zhaoxu, said only that the death sentences had been confirmed by China's highest court.

The International Campaign for Tibet, which advocates democracy and human rights for Tibet, said the two men who were executed were Lobsang Gyaltsen and Loyak, who went by only one name.

They were sentenced in death in April - Lobsang Gyaltsen for setting fire to two clothing shops on March 14, 2008, that killed a shop owner, and Loyak for setting fire on the same day to a motorcycle dealership that killed five people, Chinese state media said.

The fires and rioting broke out during anti-China protests around the anniversary of a failed 1959 uprising in Tibet against Chinese rule.

Last week, a Tibetan human rights group reported that four Tibetans had been executed October 20 in Lhasa, Tibet's capital, for murder, arson and other violent crimes committed during the anti-China rioting.

Those four men included Lobsang Gyaltsen and Loyak, the Tibetan Centre for Human Rights and Democracy (TCHRD) said, citing local sources. The centre is based in Dharamsala, India, where the Tibetan government-in-exile is headquartered.

Its US-based counterpart said, however, that the other two executions were not officially confirmed.

Violence erupted on March 14 last year in the Tibetan capital after anti-Chinese protests initially led by Buddhist monks. According to Chinese officials, 19 people died in the riots, but Tibetan exile groups said more than 100 died.

It was the worst anti-China protests by Tibetans since the end of the 1980s. From Lhasa, where the unrest escalated into attacks on Han Chinese, the protests spread to other parts of Tibet and other Tibetan-populated areas of China as Tibetans charged Beijing with political, cultural and economic discrimination.

A Chinese crackdown led to international protests that overshadowed the Olympic torch relay ahead of the Summer Games in Beijing in August 2008.

Dozens of Tibetans were sentenced to long prison terms or suspended death sentences earlier this year for offences linked to the rioting, state media reported.

The Tibetan Centre for Human Rights and Democracy said Lobsang Gyaltsen's body was handed over to his family after the execution, which was carried out my firing squad. Loyak's family was given his ashes, it said. (dpa)