AMRITSAR (India) - TOWNS and cities across the northern Indian state of Punjab were under strict curfew on Tuesday after riots sparked by the shooting of a guru in a clash between rival Sikh communities in Austria.

Army and police patrols enforced orders that shops, offices and schools would remain closed following the violence in which angry mobs torched trains, smashed bus windows and blocked roads.

The protesters were demonstrating against the murder of Sant Rama Nand, who was killed by fellow Sikhs in a temple in the Austrian capital of Vienna as he addressed 200 worshippers on Sunday.

Restrictions would remain in place across Punjab, the home to the majority of the world's Sikhs, as 'the situation is still tense', a police spokesman told AFP.

Two men died in Monday's rioting and Indian Prime Minister Manmohan Singh, himself a Sikh, issued an appeal for calm.

Sant Rama Nand, 56, died and 16 other people were injured in the Vienna temple attack, which was reportedly over a dispute about the role of castes in the Sikh religion.

A second guru, or teacher, Sant Niranjan Dass, 66, was among those wounded as Sikhs fought each other with guns and knives inside the temple.

The two gurus, who belong to a group representing low-caste Sikhs, were visiting Vienna to meet worshippers.

Leaders at the temple, which opened in 2005, have campaigned against the caste system, but their stance has angered other Sikhs in Austria. -- AFP