India's Kerala state has asked people to stay cautious but urged them not to panic after an increase in Covid cases.

The southern state has witnessed the increase after the detection of JN.1, a sub-variant of Covid-19.

It has been previously found in several countries, including the US and China.

The World Health Organization (WHO) says all approved Covid-19 vaccines will continue to provide protection against JN.1.

The southern Indian state currently has 1,324 Covid-19 active cases and reported four deaths from the disease on Saturday. Officials have attributed this to the high testing rate in the state.

But it's not clear how many of these cases are related to JN.1. Only a small number of samples are routinely genome sequenced to keep track of different variants of the virus.

State health minister Veena George said there was no need to worry and the situation was under control.

The JN.1 sub-variant was found in Kerala earlier this month in a positive RT-PCR test sample, officials said.

It was detected as part of the ongoing routine surveillance by INSACOG, a network of laboratories that has been monitoring Covid-19 in India, they said.

The patient, a 79-year-old woman, had mild symptoms of influenza-like illness and has since recovered.

Ms George on Sunday added that the variant already existed in other parts of the country.

"Months ago, this variant was detected in a few Indians who were screened at the Singapore airport," she told reporters.

Kerala's neighbouring states Karnataka and Tamil Nadu also say they are keeping a close watch on the rising cases in the state.

Meanwhile, India's federal health ministry has been running mock drills in hospitals in several states to check their preparedness to handle a sudden rise in Covid numbers. But officials have not attributed the drills to the JN.1 sub-variant.

The Indian Council of Medical Research (ICMR), however, has noted the rise in Covid cases in Kerala.

"There has been an increasing trend of Covid-19 cases from the state of Kerala since the last few weeks. This has been attributed to an increase in the number of samples from influenza-like illness (ILI) cases being referred for testing," Rajiv Bahl, Director General of the ICMR, said.