Fearing unrest, Indian police have reportedly arrested more than 500 people ahead of a Supreme Court ruling due Saturday on a hotly disputed religious site in the holy city of Ayodhya.

India's top court said late Friday it will deliver a verdict on Saturday morning on the decades-old spat over the future of a small piece of land claimed by both Hindus and Muslims that in the past has sparked deadly religious riots.

Hindu hardliners want a temple built on the site, currently barricaded off after a 16th-century mosque there was demolished during 1992 riots that left 2,000 people dead.

Hindus believe the mosque was built over the site of the birthplace of their god Ram.

Security was tightened across India in the run-up to the ruling, and Uttar Pradesh state police chief O.P. Singh told the Economic Times that more than 500 arrests had been made.

"The main message to the police force is to maintain peace at any cost," the newspaper quoted him as saying.

Most of the suspects were taken into custody while a further 70 people were detained over social media posts, he said -- warning that the internet could be blocked locally if required.

Singh added that police had also identified more than 10,000 people he described as "anti-social".

Indian authorities are fearing a repeat of 1992 riots in the holy city of Ayodhya in which 2,000 people died
Indian authorities are fearing a repeat of 1992 riots in the holy city of Ayodhya in which 2,000 people died AFP / STR

A police spokesman declined to comment to AFP.

In recent years, Ayodhya has become a rallying point for Prime Minister Narendra Modi's ruling Hindu nationalist Bharatiya Janata Party (BJP).

Some senior BJP members are being tried separately over their role in the mosque's 1992 destruction.

In 2010, a High Court divided the disputed land between Hindu and Muslim groups, but both parties appealed to the Supreme Court, which has since repeatedly put off a verdict.

Media reports say Modi has told ministers to refrain from making comments on the case that could fuel tensions.

For India's minority Muslims, the dispute and a recent clampdown in Muslim-majority Kashmir have become symbols of the hostility that they say they face from the government.

Hindus make up about 80 percent of India's 1.3 billion population, while there are about 200 million Muslims.