Indian authorities will launch a major security operation at the ruins of a 16th-century Babri mosque in Ayodhya, where hundreds of thousands of far-right Hindus are expected to gather on Sunday.
The demonstrators aim to put pressure on the government to build a new Hindu temple on the disputed site.
Constructed in 1528 by order of Babur, the first Mughal emperor of India, the mosque was razed on December 6, 1992, by Hindus who claimed the site was where their deity, Lord Ram, was born.
The incident prompted a series of massive riots which led to the deaths of about 2,000 people across the country.
Local media reported that more than 3,500 Muslims have fled the city before the gathering.
Anil Pathak, the district chief of Faizabad, where the mosque is located, said: "The government will ensure that the event passes off peacefully and the local administration has put in place an elaborate security apparatus."
"No one will be allowed to disturb peace and order in the city," he told the Reuters news agency.
More than 900 extra police and a large number of military, including elite commandos, will be deployed at Sunday's event, Vivek Tripathi, a spokesperson for the Uttar Pradesh police said.
'BJP committed to building Ram temple'
Hindu groups have insisted that there was a temple at the site before the mosque was built in the 16th century, an issue that has caused a permanent fissure in India's social fabric and instilled fear among India's Muslim minority.
"More than 200,000 people will attend," said Surendra Jain, general secretary of the far-right Vishwa Hindu Parishad, which will be holding a religious congregation at the disputed site in Ayodhya.
"We assure everyone ... that not even a twig will be disturbed."
In advance of a general election that must be held by May next year, leaders from Prime Minister Narendra Modi's Hindu nationalist Bharatiya Janata Party (BJP) - who led the Ram temple movement - have become more vocal in their demand that a new Hindu temple be built.
On Wednesday, the BJP's president said his party was "committed to building the Ram temple in Ayodhya," and would not change its stand.
Ruled by the BJP's Yogi Adityanath, a Hindu hardliner, Ayodhya is in the politically important northern Uttar Pradesh state, which is bigger than Brazil by population, and sends more legislators than any other state to India's parliament.
Adityanath has been repeatedly accused of inciting violence against the country's Muslim minority, who make up around 14 percent of India's 1.3 billion people.
