Malaysia's former Prime Minister Mahathir Mohamad said on Monday he had quit the United Malays National Organisation (UMNO), media reported, a move that could weaken the ruling coalition.
The Star newspaper, which reported the announcement in its text service, gave no details.
Mahathir, a staunch critic of his hand-picked successor Abdullah Ahmad Badawi, announced the resignation three days after the government ordered the attorney-general to investigate him and five others over the appointment of judges while he was in power.
Analysts said Mahathir, who ruled the country for 22 years until 2003, was apparently upset over the allegations.
"His departure can bring harm to UMNO and weaken PM's leadership," said political analyst Yahya Ismail.
Mahathir said at the weekend he was willing to be investigated and taken to court over the allegations.
