Cities and towns across the northern Indian state of Punjab are shut in response to a general strike called by the Sikh community.
Many of the Sikh protesters have been armed
Security forces have been deployed and businesses and schools are closed for the day amid fears of violence.
Sikhs are demanding an apology from the leader of a religious sect who appeared in an advert dressed like one of the Sikh religion's most important figures.
Sikh community leaders say it is an insult to their religion.
Last week, thousands took to the streets. One man was shot dead in clashes that followed.
Attempts to broker a settlement between the Sikhs and the sect have failed.
Thousands of extra police and soldiers have been deployed across Punjab and the state's political leadership has said peace will be maintained at all costs.
DSS supporters have come from various religions
Streets in many Punjabi cities and towns are deserted.
Thousands of machine-gun wielding soldiers are on alert and the anti-riot Rapid Action Force personnel have marched through some of the sensitive areas.
In the state of Jammu, Sikhs have held protest demonstrations, burning effigies of the leader of the Dera Sacha Sauda (DSS) religious sect.
The DSS's leader has refused to apologise for appearing in an advertisement dressed like one of the figures most revered by Sikhs, Guru Gobind Singh.
The Sikhs called it blasphemy.
Fearing possible violence by outraged Sikhs, security forces have erected barricades around the headquarters of the Dera Sacha Sauda (DSS) religious sect in Sirsa town [in the neighbouring state of Haryana].
An estimated 20,000 DSS followers live on or near the campus.
The sect also has many smaller campuses across Punjab.
Appeal for calm
Sikh leaders have demanded that all campuses where sect members live be closed within a week.
The sect claims it has 20 million members worldwide and says it is not a religion but a humanitarian organisation caring for its devotees.
Analysts say the DSS action has to be seen in the context of state elections held in Punjab in February when the sect leader issued a public appeal for people to vote for the Congress party.
Religious sects have traditionally been subtle about their support for political parties - they have usually issued internal appeals asking their followers to vote for the political party of their choice.
The trouble has been brewing for days
Most Sikhs in Punjab support the state's governing party, Akali Dal.
Some analysts say Sikh leaders, angry at the direct intervention by the DSS in the elections, seized the opportunity to whip up popular sentiments of their community against the sect.
They say the latest conflict threatens to lead to a polarisation of the communities and the dispute could trigger widespread unrest.
Although peace has prevailed in the state for the last decade or so, in the 1980s and the 1990s, Punjab was the site of a violent insurgency by Sikhs who desired an independent homeland.
In 1984 Indian security forces killed many Sikh militants after they seized the Golden Temple in Amritsar, the Sikh religion's most important site.
In revenge, Indira Gandhi, the then-prime minister, was shot dead by her Sikh bodyguards.