A team of archaeologists has started excavations in the northern Indian town of Ayodhya at a holy site claimed by both Hindus and Muslims.
The archaeologists must complete the excavation in a month
They are aiming to settle a dispute over whether there was once a Hindu temple there.
The site houses the remains of a 16th century mosque destroyed by Hindus in 1992.
They say the mosque was built on the ruins of a temple which marked the birthplace of the Hindu God, Ram.
The destruction of the mosque sparked off religious riots across India in which more than 2,000 people died.
Last week, a court ordered the excavation of the site to determine if a temple ever existed there.
Some Indian historians have already raised doubts about the excavation, arguing that it could lead to more historical disputes.
Representatives from India's small Jain community have joined in the dispute, saying one of their ancient temples may also have existed in Ayodhya.
"The digging in accordance with the court order began at 1335 local time," Magistrate Amok Kumar, from the nearby city of Faizabad, told journalists on Wednesday.
Nearly 80 labourers are involved in the dig, which is being supervised by the Archaeological Survey of India (ASI).
A Muslim representative, Zafaryab Jilani, has given his support to the dig: "I am fully satisfied with the process adopted by the ASI."
The excavation was delayed when a court ordered the archaeologists to carry out a second survey of the site on Wednesday, which would be witnessed by the different sides in the dispute.
The 15-member team arrived at the controversial site on Monday under heavy guard.
A model of the proposed temple at a Hindu workshop near Ayodhya
They spent the day surveying and mapping the area before presenting their plan for excavation to the local administration, which is responsible for security at the site.
The archaeologists are banned from talking to the media about their work.
The right-wing Vishwa Hindu Parishad (VHP, Hindu World Council) has said it will hold a week-long protest next week in Ayodhya demanding the handover of the site.
Under the court order, no digging can take place on the core area which now houses a makeshift Hindu temple.
It also said that the exercise should not disrupt Hindu devotees from praying at the site, which is now allowed at restricted times.
Both sides to the dispute have also been asked to nominate representatives who can monitor the process.
But access to the site has been denied to the media.
'Chances not high'
The VHP, which wants the area to be handed over so that they can begin constructing a temple, is hoping for a favourable outcome.
A senior leader, Vishnu Hari Dalmiya, said that his colleagues had dug in the area in the past and found the remnants of a temple.
But a former director general of the Archaeological Survey of India, MC Joshi, told the BBC the chances of finding the temple of the Hindu God, Ram, were not high.
"We will tell the court whatever we get after a month of excavations," he said.
The head of the Muslim organisation, the Indian National League, Ibrahim Suleman, has warned that the excavation will further complicate the dispute.
The court has asked for the excavation to be completed in a month and for a report of the findings submitted to it.