Police said today they were intensifying security amid tense campaigning for a by-election seen as a key test for the opposition ahead of general elections expected before 2009.

The rural seat of Ijok in Selangor goes to the polls on Saturday following the death earlier this month of the incumbent lawmaker from the ruling Barisan Nasional coalition.

Selangor police chief Ismail Omar said more security measures were needed to control what he said were highly-charged emotions of supporters on both sides ahead of the election.

He said about 1,000 extra officers would be sent to support the district's police force.

"We hope that supporters on both sides will use their good sense and maturity. They are the key elements that would ensure the election is carried out without any riots," Ismail told AFP .

"Everything has been under control in the last 24 hours. There have been no incidents reported," he added.

All entry and exit points in Ijok town had already been secured with roadblocks, he said.

Violence condemned

Scuffles broke out in Ijok last Thursday between hundreds of rival supporters of the BN and the opposition PKR during the nomination of candidates.

Both sides see Saturday's vote as a key test ahead of general elections expected before 2009.

In another incident last Friday, PKR's candidate Khalid Ibrahim was threatened by a group of BN supporters, according to prominent blogger and freelance photographer Jeff Ooi.

"One of them started probing Khalid with intimidating questions. We got out of there and into our car but we were already surrounded by 20 of them," said Ooi, who was with Khalid.

Ooi said one of the supporters hit a fellow photographer also in the car in the face with a broken plastic water bottle, while others threatened to break both their cameras.

Rights group Suaram today condemned the violence and criticised what it said was uneven treatment of opposition party supporters by police, accusing them of stopping a PKR rally yesterday.

"While the police have failed to act against the intimidators, they have, on the other hand, been swift when it came to stopping the opposition from campaigning," it said.