In the Uttar Pradesh city of Meerut, about 90 km (55 miles) from New Delhi, nearly 3,000 police were deployed, four times more than last Friday
Indian authorities stepped up security in major cities on Friday and suspended mobile data services in some places in an effort to maintain order ahead of protests planned against a new citizenship law.
At least 25 people have been killed in protests across the country since the law, seen as discriminatory towards Muslims, was adopted on Dec. 11.
The backlash against the law, pushed through parliament by the Hindu-nationalist government of Prime Minister Narendra Modi, is the biggest challenge he has faced since he was first elected in 2014.
Violence peaked last Friday when police clashed with protesters in several cities after weekly Muslim congregational prayers, especially in India's most populous state of Uttar Pradesh.
With more protests expected this week, the Uttar Pradesh administration banned mobile internet services in many parts of the state, including in the provincial capital Lucknow, the state government said.
In the Uttar Pradesh city of Meerut, about 90 km (55 miles) from New Delhi, nearly 3,000 police were deployed, four times more than last Friday, the city's police chief told Reuters.
At least five people were killed in the city last Friday.
A Reuters witness saw a riot control vehicle with a tear gas cannon mounted on its roof. A vehicle carrying a water cannon was stationed nearby as several policemen in riot gear kept watch.
"We're working with local politicians, religious leaders and community members to appeal for calm," Ajay Kumar Sahni, Senior Superintendent of Police in Meerut said.
"We expect the situation to remain normal."
In the capital of New Delhi, police imposed an emergency law in some parts of the city, forbidding large gatherings, news channels reported. Such prohibitions have been in place in Uttar Pradesh for more than a week.
Despite the restrictions, thousands are expected to gather for protests after Friday prayers in Delhi, Mumbai, Kolkata, Ahmedabad, Bengaluru and Chennai, protest organisers said.
The citizenship legislation makes it easier for minorities from India's Muslim majority neighbours - Afghanistan, Bangladesh and Pakistan - who settled before 2015 to get citizenship.
Critics say the exclusion of Muslims is discriminatory and that the award of citizenship based on religion violates India's secular constitution.
Muslims, India's second biggest community by religion, account for about 14% of its 1.3 billion people.
The protests have come as India's economic growth has slumped to its lowest in more than six years and unemployment remains high.