Marianne Kearney, Jakarta – At least 100 soldiers armed with grenades, bazookas and rifles attacked a police station in North Sumatra on Sunday night, killing four policemen and leaving 27 injured.

The provocation was apparently the arrest of a soldier by the police for alleged drug use.

Clashes of this type are not uncommon in Indonesia and are symptomatic of the power struggle and tensions between the two forces, said analysts.

Describing the attack in Binjai, a small town on the outskirts of Medan, North Sumatra, local police spokesman Commander Amrin Karim told The Straits Times: "The situation was out of control. They arrived and just ran amok. They were using rifles, grenades and even a type of bazooka."

Four police officers were shot fatally in the chest, 27 were injured, four of them critically, he said. In addition, the police headquarters and dormitories were totally destroyed.

The assault came in retaliation for the arrest of a soldier on the charges of selling shabu-shabu or Ecstasy pills, he said. "We try to apply the law but the TNI does not accept it. Because they don't believe the police have the right to charge the military," he said. TNI refers to the Indonesian military.

After unsuccessfully demanding that their colleague be released, several soldiers attacked the police with bayonets on Saturday night, according to local newswire reports. The following night, around 100 soldiers returned to launch an attack that went on for several hours. Calm was restored only in the early afternoon yesterday. More than 60 prisoners managed to escape during the attack.

The Binjai police had initially requested back-up troops but later withdrew the demand after police and military commanders met and ordered their troops to halt the attack. A hunt is now on for the attackers.

North Sumatra Army spokesman Brigadier-General Ratyono said: "We will investigate this and fire those who were involved in this incident." This was not the first time that the military clashed with the police in Binjai, admitted Commander Amrin. A similar but smaller clash erupted several months ago when police arrested a soldier for gambling.

In other such instances across the country, three teenagers were killed by stray bullets when a petty fight between the elite Kostrad troops and the police turned ugly in Madiun, East Java, last September.

Especially prone to such incidents are the conflict-ridden areas like Aceh and Maluku. There is often an overlap of the security forces' roles in these regions which gives rise to rivalry and animosity.

Historically, the roots of resentment lie in the fact that the police used to be mainly a back-up force under military command. Only during former president Abdurrahman Wahid's time was it carved out and charged with the task of maintaining internal security while the military was entrusted the task of national defence.