A farmer angry over a court ruling set off a bomb in a Chinese courthouse, killing himself and four other people, a news report said Saturday.

The explosion Friday in Minle County in the northwestern province of Gansu killed the president of the county court and a local Communist Party official, the official Xinhua News Agency said.

The bomber was identified as Qian Wenzhao, 62, a farmer who Xinhua said was angry over a ruling in a property dispute involving the house of his late son and daughter-in-law.

Qian forced his way into a meeting room on the courthouse's fourth floor and ignited explosives, Xinhua said.

"Police believe it was Qian's resentment against the court verdict that had led to the blast," the report said.

The slain court president, Chen Xingrong, and the party official, Wang Qiang, were attending the meeting, Xinhua said. It didn't say whether they were the targets of the attack or identify the other victims.

Bomb attacks motivated by grudges or business disputes are common in China, where most gun ownership is banned but explosives are widely available for mining and construction.