Police in Tamil Nadu is using drones to monitor the lockdown extended in four districts of the State, including capital Chennai put in place to curb a surge in the number of COVID-19 positive cases.

"We have started enforcing the lockdown measures. In many areas of the city, we are not only monitoring the situation through drones but even making an announcement through drone speakers. Vehicles will not be allowed in these cities except for permitted purposes," Chennai Police Commissioner AK Viswanathan told ANI.

The state government has announced 12-day long lockdown till June 30 in Chennai, Thiruvallur, Kancheepuram and Chengalpet districts in the wake of a rise in the COVID-19 positive cases in the districts.

Tamil Nadu recorded 2,141 positive cases of COVID-19 on Thursday, bringing the State tally to 52,334. Among these, Chennai reported 1373 positive cases, bringing the city's total to 37,070.

The death toll in the State is at 625 after 49 deaths were reported on Thursday, the health department said.