The remaining suspect was arrested.
The report in Tianshan Net, a news portal run by Communist Party officials in Xinjiang, was the first official confirmation of the bloody September 18 mine attack, which had been reported in some foreign media but was kept tightly under wraps in China.
China blames the violence in Xinjiang on terrorism, but authorities typically are reluctant to release details and have blocked information on some deadly incidents.
That has drawn criticism that Beijing keeps control of the narrative to serve its agenda in the region, which is rife with ethnic conflict between members of the Muslim Uighur minority and the country’s Han majority.
Tianshan said the assailants went into hiding after they killed 11 civilians and five police officers at the coal mine at a remote location in the Asku region.
The coal mine is controlled by members of China’s Han majority.
Radio Free Asia (RFA) - which is funded by the US government - was the first to report on the mine attack in September.
Inquiries at the time with local officials yielded no information because they either did not answer phone calls or claimed no knowledge of the attack.
Tianshan said authorities launched a massive manhunt in the mountainous area and that police killed 28 assailants and apprehended the remaining suspect by November 12.
The assailants made several contacts with overseas organisations before and after the attack, Tianshan said, without elaborating on the groups.
The Tianshan report came three days after RFA, citing named local sources, said police killed 17 suspects from three families, including women and children, who were accused of carrying out the mine attack.
RFA said 50 people were killed in the mine attack - a far greater number of victims than reported in the Tianshan account.
Some critics say the violence in Xinjiang stems from government policies that have marginalized the Uighurs, and also warn that Beijing’s harsh crackdown may be radicalizing some Uighurs.
The government says it treats its minorities fairly and spends massive amounts to boost living standards.
Hours after the terrorist attacks in Paris on November 14, China’s Ministry of Public Security carried a brief statement that was believed to refer to the mine attack and the following manhunt against “terrorists.”
The statement declaring “a major victory” was quickly removed without any explanation but not before overseas Uighur rights advocates questioned whether Beijing tried to fan hostility toward Uighurs by riding on the public sentiments following the Paris attacks.
The full report on Tianshan was released six days later.