Violence broke out at a forum attended by former Malaysian prime minister Mahathir Mohamed on Sunday, a member of Mahathir's party said.
The 92-year old Mahathir, chairman of the opposition party Bersatu, was speaking at a town-hall session on Sunday when shoes, chairs and flares were thrown at him, the party's youth chief, Syed Saddiq Syed Abdul Rahman, told reporters.
Mahathir was safely escorted out of the event and did not suffer any injuries, the former premier's aide told Reuters.
Local media reported that several others were injured and that two men have been arrested in connection to the violence.
"Unfortunately, there were elements... we feel and believe were aimed at sabotaging the programme and hurting Dr Mahathir," Syed Saddiq said at a press conference, a video of which was posted online.
"We saw bottles, shoes, chairs and flares... They were not being thrown to the back or to the left or right but were clearly directed towards Dr Mahathir," he said.
Mahathir has been campaigning to oust Prime Minister Najib Razak over alleged graft linked to scandal-ridden state fund 1Malaysia Development Berhad (1MDB). Najib denies wrongdoing.
Mahathir chairs a fractured opposition alliance and has offered to head the government again if it wins an election that is due by next year.
Last month, Mahathir challenged Najib - his former protege - to debate allegations of corruption and mismanagement levelled against them both during their terms in office. The Sunday event - dubbed "nothing to hide" - would have included the debate, but Najib wasn't expected to show up and did not appear.
1MDB is the subject of money-laundering investigations in at least six countries. The U.S. Justice Department alleged in civil lawsuits that about $4.5 billion of funds were misappropriated from the fund.
In its latest court filing on Thursday, the U.S. Justice Department said it was conducting a criminal investigation of 1MDB and asked for a stay on civil lawsuits it had filed to seize assets allegedly bought with money stolen from the fund.
Najib denied taking money from 1MDB after it was reported that investigators traced nearly $700 million to his bank accounts. Authorities cleared him of any wrongdoing, saying the money was a donation from Saudi Arabia.
