NEW DELHI (AFP) - Scores of workers were racing against time on Monday (Oct 28) to try to rescue a two-year-old boy trapped for more than 72 hours down a 26m well in south India, officials said.

The boy fell into the 30cm diameter pipe on Friday afternoon while playing near his home in Tiruchirappalli district of Tamil Nadu state.

A thermal camera was briefly used to monitor the child's body temperature while oxygen was supplied through a pipe.

The toddler, Sujith Wilson, was unconscious but breathing until Sunday morning, but rescuers have been unable to check his condition since then.

Authorities said the child was initially wedged at around 9m before slipping to the bottom in an upright standing position.

"It's a race against time," said Jawaharlal Nehru, a senior district officer at the site.

Workers used an oil drill to dig a hole parallel to the well on Sunday, but the rig broke down at around 10m because of the rocky ground.

Attempts to use robotic devices to lower ropes to latch onto the boy's wrist failed on Saturday.

The incident is the latest in series of mishaps that have seen children accidentally fall into disused and uncovered wells in rural India.

In 2006, the rescue of a six-year-old child made headlines when he was recovered safely in Haryana state after being stuck in an 18m well for 48 hours.