Updated

A group of Western ambassadors have written to the Vietnam's Communist leaders to call for the release of a peaceful democracy activist described as being in the final stages of cancer.

Dinh Dang Dinh, a former chemistry teacher, is serving a six-year sentence for "spreading propaganda" against the state

In a letter sent Thursday to Vietnam's foreign minister, the ambassadors of the U.S., EU and other missions urged Dinh be released on humanitarian grounds "so he can spend his remaining time at home or if necessary in a hospital."

Dinh's daughter, Dinh Phuong Thao, said Dinh was moved to a police hospital Tuesday, but the family had not been told whether he would be returning to prison.

Thao and the ambassadors said Dinh had stomach cancer that had spread to his lymph nodes.

"We are very, very worried about his situation," said Thao. "Our hope is that we can get him out of prison."

She said that previous requests to have him transferred had been turned down.

The government didn't immediately respond to a request for comment, something that is not uncommon.

Dinh's family said he was a "patriot" who wanted a more pluralistic political system and had opposed a large bauxite mine in the central highlands owned by the government and built by Chinese contractors, a flashpoint issue taken up by anti-government protesters, nationalists and environmentalists.

Vietnam is under international pressure to release dissidents and loosen restrictions on freedom of expression and political assembly, but there is little sign the government is considering meaningful reform anytime soon.