Hindu zealots reduced the Babri mosque to rubble in 1992, kicking off riots across India that left thousands dead, most of them Muslims, and the future of the site has become a major touchstone issue in Indian politics.
Standing behind yellow steel barricades, police on Thursday were seen checking vehicles and stopping some passers-by for questioning as they sought to prevent any flare-up in violence.
Watchtower guards and security cameras were trained on the ruins of the Babri mosque and its surroundings. The disputed site is protected by a high steel fence.
Many Hindus believe Ayodhya marks the birthplace of the deity Ram, and that the mosque that stood there for 460 years was only built after the destruction of an earlier temple.
Prime Minister Narendra Modi's Hindu nationalist Bharatiya Janata Party (BJP) came to power in 2014 pledging to construct a temple on the site, but the issue remains tied up in the courts.
Modi, running for a second term in 2019, has faced some disquiet from his core supporters who feel that he has not done enough for the cause, despite his parliamentary majority.
Uttar Pradesh's state premier Yogi Adityanath, a firebrand monk who has long campaigned for the temple, has also unveiled plans to build the world's largest statue in Ayodhya -- a 221-metre (725-foot) bronze Ram.
On an average day, a few thousand Hindu devotees visit the makeshift temple that was established after 1992. But on Thursday fewer devotees could be seen.
Muslim groups meanwhile held small commemorations of those who lost their lives in 1992.
"All we want is peace and harmony. Muslims and Hindus of Ayodhya have always lived in harmony but it is the politicians who stoke hatred for their electoral gains," said Mohammed Shahzad who runs a meat shop in the city.
"The mosque in my neighbourhood was attacked during the riots in 1992. Our home was set on fire, we somehow managed to save our lives. We don't want a repeat of the violence at any cost."
Kalyani Ubhe, a tourist, said: "A temple must be built here. It is a matter of Hindu faith and devotion. We have a right to pray at the birthplace of Lord Ram."
A statue will be a "bonus", said Shyam Madho, a 70-year old Ayodhya resident.
"The statue will serve the purpose of tourism. It's the temple which is the main thing. First a temple must be built then the statue."