Supporters wait as Malaysia's opposition leader Anwar Ibrahim submits his election nomination in Berapit, April 20, 2013
Hundreds of cases of Malaysian election violence including a bomb explosion have been reported since campaigning for tightly contested May 5 polls got under way four days ago, police said Wednesday.
In the latest incident a bomb exploded in northern Penang state late Tuesday near a political gathering of the ruling Barisan Nasional coalition, resulting in a 35-year-old security worker being injured by flying debris.
"It was a time bomb. But it did not contain any splinters or shrapnel," Rosli Chik, local police spokesman told AFP.
Police later found a second bomb in the area and detonated it.
Prime Minister Najib Razak and opposition leader Anwar Ibrahim condemned the culprits responsible for planting the bombs.
"The timing of the explosion and location of these devices are highly suspicious and are clearly meant to create fear and provoke disorder," Anwar said in a statement.
A total of 387 incidents were reported in the first three days of the two-week campaign, which kicked off Saturday, and at least 15 people have been arrested over the violence, national police spokesman Ramli Yoosuf told The Star newspaper.
"They were in possession of weapons such as machetes and suspected of slashing rival party supporters and criminal intimidation, mostly while putting up flags and banners," Ramli was reported to have said.
He added that hundreds more incidents had been reported earlier, between the April 13 dissolution of parliament and the official start of campaigning.
The pro-government newspaper gave no indication of who was carrying out the acts of violence. The opposition has complained that their supporters have been victims in most of the attacks, although AFP has been unable to confirm this.
Malaysia is bracing for long-anticipated elections that experts say could herald the country's first change of regime since independence from Britain in 1957.
The vote pits a coalition -- dominated by the United Malays National Organisation (UMNO) that has ruled Malaysia with a tight grip for 56 years -- against an upstart opposition promising a more liberalised society.
The independent group Bersih, which advocates clean elections, had previously warned that political violence and intimidation could potentially sway the expected close vote.
Ramli said the cases of violence included individuals attempting to run down rival political supporters in cars, adding that one election operations centre in a northern state was set on fire, but giving no other details.
No deaths have yet been reported, but Malaysian media last week reported a man was left in a coma after a beating by ruling party supporters in the north of the country. The man was later reported to have regained consciousness.