Despite the boisterous teasing, jeering and singing of party songs at SK Sri Penanti, most of it took place in good spirits.

The two sets of supporters from Pakatan Rakyat and Barisan Nasional were separated by a single-carriage road under the flyover leading to the SK Sri Penanti.

There were about 1,000 to 1,200 people there, with almost 60 percent of them from Pakatan.

scuffle tense situation in permatang pauh by election polling day 260808 04 BN took turns to sing the Umno party and Barisan Kita songs while Pakatan continuously called for BN to step down.

Though the police presence was heavy, with some nine FRU trucks on standby, both sides behaved themselves pretty well.

That was until a moment of madness.

At 10.30am, after PKR candidate Anwar Ibrahim and his family had left the polling station, one supporter sporting a PAS cap was arrested.

scuffle tense situation in permatang pauh by election polling day 260808 03 According to an eyewitness, he saw a projectile from the PKR side of the crowd. The missile, however, did not reach the BN crowd across the road.

Seconds later, a young man rushed across the divide, which was marshalled by policemen.

At that moment, the man was caught by the police and hauled to the Kubang Pasu police station.

Two units of FRU were immediately brought into the area to ensure that the rest of the crowd did not react physically.

Refused to heed warning

Using a loud hailer, an officer directed the crowd back and stationed the FRU units in front of the crowd. He gave them another five minutes to disperse.

scuffle tense situation in permatang pauh by election polling day 260808 01 But Batu MP and PKR information chief Tian Chua arrived at the scene and after negotiating with the police, the crowd was allowed to remain there.

According to Penang police chief Ayub Yaakob the man was detained for throwing objects and obstructing the police from discharging their duties.

"The man refused to heed police warnings and threw an object at the other side. He also attempted to stop police from doing their work," said Ayub.

Umno vice-president and also Malacca CM Ali Rustam visited the polling station at 11.10am.

Until about 2pm, some 200 boisterous Pakatan supporters remained at the voting centre, prompting the police to go on standby to swing into action in the event of any untoward.

Watch 2-min video of the tense stand-off

Permatang Pauh: Mother of all by-elections