NEW DELHI, JULY 8 -- Six persons were killed in northern India today in scattered violent reactions to Monday's and Tuesday's massacres of bus passengers by gunmen believed to be Sikhs, according to official reports and news agency accounts.

The victims were not identified by religion, but it was clear that today's incidents involved attacks on Sikhs by Hindus.

In one incident, however, the victims could have been Hindus since reports referred to shooting from a besieged temple, apparently occupied by Sikhs.

Widespread protest strikes closed shops and offices throughout the states of Punjab, Haryana, Himachal Pradesh and parts of Uttar Pradesh, and more strikes were called for Thursday.

A total of 72 persons, all believed to be Hindus, were killed Monday and Tuesday nights when gunmen believed to be Sikh militants stopped buses in Punjab and Haryana states and opened fire on the passengers.

Initial expressions of shock quickly gave way to outrage and demands for action. The Army and paramilitary police units were put on alert in northern India and the capital in response to rising tensions between Hindus and Sikhs who often live side by side in cities and towns across northern India.

Reports reaching New Delhi tonight spoke of two deaths during scattered rioting in Rishikesh in Uttar Pradesh state. The temple shooting incident occurred at Rishikesh, a holy city to Hindus that was the destination of the bus intercepted by the gunmen Monday.

Three persons were reported beaten to death or lynched in Haryana near the scene of Tuesday night's killings, and one person was reported killed in New Delhi. In other incidents, people were dragged off trains or from cars and trucks and beaten by mobs before police could intervene.

There were numerous reports of stonings and arson and looting of shops owned by Sikhs.

Prime Minister Rajiv Gandhi met tonight with opposition leaders to work out tightened security measures.