An Indian woman has given birth to a 15lb (6.8kg) baby girl that doctors say could possibly be the heaviest child ever born in the country.

The infant weighs the same as a six-month-old in a country where new-born babies normally weigh 2.5-3.5kg.

Her mother Nandini, 20, gave birth by a Caesarean section, at a hospital in the southern state of Karnataka.

Doctors said they were conducting tests to find out the reason why the baby was so heavy.

"It is the biggest baby in India, I can say. Whether it is the biggest in the world, I cannot say right now," Dr Venkatesh R, district health official in Hassan district, told BBC Hindi's Imran Qureshi.

The baby is not just heavy, she is also very tall, doctors said.

"The baby's height is 62cm (24.4in) as against the normal Indian baby's height of 50cm," said Dr SR Kumar, who is looking after Nandini and her baby.

Since overweight newborns are normal in cases where the mother is diabetic, the first thing the doctors did was to check if Nandini had diabetes, but they found to their surprise that she had had no such complaints.

"We have done an ultrasound and conducted blood tests on Nandini, but we didn't find any abnormality," Dr Kumar said.

"We have sent the samples for a test called an inborn error of metabolism. We should get the result after 48 hours."

The record so far for the heaviest Indian baby is held by a boy, born to Firdous Khatun of Uttar Pradesh in November 2015. The baby boy weighed 14.77lb (6.7kg).

The world record for the heaviest baby was for a boy born to Carmelina Fedele in Aversa, Italy, in September 1955. The boy weighed 22lb 8oz (10.2 kg).