KUALA LUMPUR - Seven Umno leaders face the risk of suspension after they publicly disparaged the ruling party, said Secretary-General Datuk Seri Tengku Adnan Tengku Mansor.

Without disclosing the identities of the seven leaders,Tengku Adnan said an Umno committee was investigating the matter and would present its findings to the presidential council and the disciplinary board, the Malaysian Insider reported on Wednesday (Oct 28).

"Once the process goes, we will suspend their membership and the positions that go with it," he was quoted as saying by the news portal.

"We can't take all this sort of nonsense anymore. If you don't believe in the party struggle, you leave the party."

Tengku Adnan, who is also federal territories minister, said Umno had its own constitution and code of ethics to which all members should adhere.

On Oct 12, a group of Umno veterans led by influential former prime minister Mahathir Mohamad accused Prime Minister Najib Razak of abuse of power for detaining a former Penang Umno leader and a lawyer under an anti-terror law.

Khairuddin Abu Hassan had been on a global campaign to highlight alleged graft involving state investor 1Malaysia Development Berhad (1MDB) before his arrest last month. His lawyer Matthias Chang was also arrested.

Both were charged under the Penal Code with attempting to sabotage Malaysia's economy and financial system.

Speaking at a news conference, Mahathir and the other Umno veterans called for Najib's resignation as prime minister. The veterans included Umno deputy president Muhyiddin Yassin, party vice-president Shafie Apdal and former Umno secretary-general Sanusi Junid.

Mahathir has been criticising Najib over his alleged mismanagement of the country, from alleged financial irregularities over1MDB and a RM2.6 billion (S$848 million) donation deposited in Najib's private accounts, to the use of new detention law Security Offences (Special Measures) Act 2012 (Sosma) against government critics.