A one-and-a-half-month-old baby boy in Delhi has died of coronavirus becoming the country's youngest victim of the infection which also affected a 12-day-old infant girl in Bhopal, as COVID-19 cases jumped by over one thousand for the sixth straight day on Sunday prompting authorities to scale up rapid antibody based blood tests.

Coronavirus infections crossed 16,000 with 1,324 cases being reported in the last 24 hours and the death toll surpassed 500, according to the Union Health ministry data, as Uttar Pradesh became the seventh state after Maharashtra, Delhi, Tamil Nadu, Madhya Pradesh, Rajasthan and Gujarat to record over 1,000 COVID-19 infections.

In Maharashtra, there was a big spike in the cases to touch 4,200. A state Health official said there were 552 new cases in the last 24 hours.

Citing the Tablighi Jamaat congregation in the national capital last month, which emerged as a major coronavirus hotspot, and the large inflow of travellers from other countries to Delhi as the reasons for the spread of the virus, Chief Minister Arvind Kejriwal said Delhi was 'fighting a difficult battle'.

"Delhi bore the brunt of maximum travellers from other countries. Delhi also bore the brunt due to an incident in the (Tablighi) markaz," he said during a video conference.

The Delhi government will not relax the lockdown for at least a week as the coronavirus spread appears to have gained pace, he said, asserting the decision has been taken to save lives.

Citing instances of asymptomatic people testing positive for the virus, Kejriwal said out of 736 samples collected recently, 186 were found infected by COVID-19 and the people did not know they were carrying the virus.

After a week's hiatus, Tamil Nadu reported 100 plus coronavirus cases again on Sunday, pushing the total number of affected people to 1,477, and authorities expanded their testing footprint with rapid test kits imported from China.

As many as 105 tested positive, including two journalists and a Sub Inspector, officials said in Chennai.

Addressing the daily media briefing, Lav Agarwal, Joint Secretary in the Union Health ministry said in 56 districts across 23 states and UTs, there has been no new COVID-19 case in the last 14 days.

In Delhi, officials said the one-and-a-half-month-old baby died at Kalawati Saran Children's Hospital attached to the Centre-run Lady Hardinge Medical College.

"The baby was brought to the hospital a few days ago. He tested positive for COVID-19. The child was admitted to SARI (Severe Acute Respiratory Illness) ward and died yesterday," a doctor at the hospital said on the condition of anonymity.

The surveillance team has been informed for contact tracing, he added.

A 12-day-old baby girl tested positive for coronavirus in Bhopal on Sunday, with health officials stating she may be the youngest COVID-19 patient in Madhya Pradesh and possibly the country.

The infant's father said it was possible she got the infection from a woman health worker who was on duty during the birth and tested positive later.

"The mother and the infant tested positive on Sunday," Bhopal's Chief Medical and Health Officer (CMHO) Dr Prabhakar Tiwari told PTI.

Soon after procuring rapid antibody test kits, the Delhi government on Sunday began testing people for coronavirus in various containment zones spread across the city, officials said.

According to Delhi Health Minister Satyendar Jain, the AAP government has acquired 42,000 such kits.

The rapid antibody tests were initiated for all the containment zones across the national capital, officials said.

The number of containment zones in Delhi on Saturday had increased to 76, with eight new zones being added in various areas in one day.

The rapid antibody test is less expensive and the result can come in 20-30 minutes, experts said.

These tests are generally used in hotspots where the infection is found concentrated in a given area.

The Kashmir Valley also received the first batch of 9,600 rapid test kits.

The kits would be used in the 83 red zones on a priority basis to help the administration expand the testing in these designated areas, an official said.

"We have received the first batch of 9,600 rapid testing kits," Director, Health Services, Kashmir, Dr Samir Mattoo told PTI.

Mattoo said the kits were being dispatched to red zones in the Valley and it would be distributed to each such containment zone to test for COVID-19 cases.

With Bhubaneswar being identified as one of the coronavirus hotspots in the country, the Odisha government stepped up its measures to fight the disease by adopting rapid and pool testing methods.

The rapid and pool tests will be conducted apart from regular sample tests, said Health and Family Welfare Minister N K Das.

"Rapid tests have started in Bhubaneswar, which reported 46 of the total 61 coronavirus cases in Odisha, while efforts are on to commence pool tests of samples at VIMSAR, Burla from Sunday," the minister said.

The death toll due to COVID-19 rose to 519 and the number of cases climbed to 16,116 in the country on Sunday, registering an increase of 31 deaths and 1,324 cases since Saturday evening, according to the Union Health ministry data.

A total of 2,301 people have recovered, it said.

"Our figures are being reconciled with ICMR," the ministry said on its website. On Saturday, the Indian Council of Medical Research (ICMR) said 16,365 individuals in the country have so far been confirmed positive for the infection.

According to a PTI tally based on reports from states, there were 16,285 positive cases while 2,464 had recovered and the death toll stood at 538.

As per the tally, the highest number of cases was in Maharashtra(4,200), followed by Delhi(1,893), Gujarat(1,604), Tamil Nadu(1,477) Rajasthan(1,431), Madhya Pradesh(1,407) and Uttar Pradesh(1,084)

In an indication of ramping up testing, an ICMR official said 37,173 tests were done on Saturday taking to 3,86,791 the total number of tests conducted so far.

The 31 coronavirus deaths reported since Saturday evening include--10 each from Gujarat and Maharashtra, three each from Punjab and Uttar Pradesh, two from West Bengal and one each from Delhi, Madhya Pradesh and Karnataka.

Of the 519 deaths, Maharashtra tops the list with 211 fatalities, followed by Madhya Pradesh at 70, Gujarat at 58 and Delhi at 43 and Telangana at 18 followed by other states, according to official data.