A high-ranking official in the Chinese city of Panzhihua is thought to have shot the mayor and the local party secretary before killing himself.
The head of the city's Land and Resources Bureau reportedly burst into a meeting of city leaders before opening fire.
The mayor and party secretary suffered injuries that are not life-threatening, Xinhua news agency reports.
Such shootings are rare in China, which has tough rules on gun ownership.
Last week, a woman who ran a street stall where customers could pay to shoot balloons with low-powered air rifles was sentenced to three-and-a-half years in prison, the BBC's John Sudworth reports from Beijing.
The attack took place at the convention and exhibition centre in Panzhihua, a city of 1.2 million people in the south-western province of Sichuan.
The gunman was later found dead on the second floor of the building, Xinhua reports. No motive for the attack was given.