India's new strain of COVID-19 cases rose to 25 after five more cases have been reported on Thursday, said the health ministry.

Of the new cases, four have been traced by National Institute of Virology in Pune and CSIR- Institute of Genomics and Integrative Biology in Delhi. The infected individuals have been kept in physical isolation at state health facilities.

The health ministry official said, "A total of 25 cases of mutant United Kingdom virus detected in India after genome sequencing. Four new cases found by NIV, Pune and one new case sequenced in IGIB, Delhi. All 25 persons are in physical isolation at health facilities."

The new variant of the virus detected in Britain has triggered widespread concern and travel restrictions across the world.

The variant of the coronavirus, which could be up to 70% more transmissible, is spreading rapidly in Britain, although it is not thought to be more deadly or to cause more serious illness, according to Prime Minister Boris Johnson and his board of scientific advisors.