Indian Council of Medical Research (ICMR) senior scientist R Ganga Ketkar said 47,951 tests for COVID-19 have been conducted in the country till date.
In a sweeping nationwide hunt, authorities across states have identified more than 6,000 people who attended the Nizamuddin Tablighi Jamaat congregation, the biggest COVID-19 hotspot in India, as more than 375 fresh cases of infection emerged on Wednesday to take the tally to close to 1,900 with at least 55 deaths.
More than 5,000 of those identified to have attended the congregation have been quarantined, including in hospitals across states, while efforts are on to trace another 2,000 including in Gujarat, Tamil Nadu and Telangana.
The list includes foreigners as well, while some of those identified by the state authorities are yet to return from Delhi to their respective native places.
Authorities attributed the big spike in the numbers of confirmed coronavirus cases largely to the Tablighi Jamaat, an orthodox Muslim society set up nearly 100 years ago by Deobandi Islamic scholar Maulana Muhammad Ilyas Khandhalawi as a religious reform movement and to spread the faith.
The latest Union Health Ministry update put the nationwide tally of the confirmed COVID-19 cases at 1,637, after 376 new cases were recorded in the last 24 hours, and the death count at 38. But figures announced by different states and union territories totalled 1,894 with at least 55 deaths.
The Ministry officials said cases have increased largely due to Tablighi Jamaat congregation, which took place in mid-March, and therefore technically it does not show a national trend. They urged people to follow guidelines during lockdown period and avoid congregations, including religious gatherings.
Maharashtra, Tamil Nadu and Delhi were among the places to report a large number of new cases.
In Delhi, the authorities said coronavirus cases have risen to 152, including 53 who attended the Nizamuddin congregation.
The number in Maharashtra increased by 33 to 335 on Wednesday, including 30 in Mumbai alone. The tally can increase further as nearly 5,000 quarantined persons are in the high-risk category, according to the state government.
In Tamil Nadu, 110 people who returned from Tablighi Jamaat meet in Delhi have tested positive, taking the total cases in the state to 234.
In Tamil Nandu, at least 515 persons have been identified for having attended the Nizamuddin meet, while at least 59 of them have been quarantined. Chief Minister K Palaniswami said 1,131 men have returned to the state of the about 1,500 people who went for the event.
In Telangana, 50 of the 57 positive cases had attended the gathering, while the state authorities have identified and quarantined at least 840 people linked to the event. The search is on for 160 others.
In Delhi also, Deputy Chief Minister Manish Sisodia said 2,361 people were evacuated from the place of the Nizamuddin congregation, out of which 617 have been admitted to hospitals for showing COVID-19 symptoms while the rest are quarantined.
Chief Minister Arvind Kejriwal said authorities are tracking mobile phones of people under quarantine to check their movement.
The Centre on Wednesday also asked all states and Union Territories to launch on a "war footing" the contact tracing of all participants of the Tablighi Jamaat congregation in Delhi's Nizamuddin, which has emerged as the coronavirus hotspot.
In a video conference with chief secretaries and DGPs of all states and Union Territories (UTs), Cabinet Secretary Rajiv Gauba also asked them to take action against foreigners, who participated in the missionary activities of the Tablighi Jamaat, for violation of visa conditions.
In Karnataka, at least 50 foreigners have been quarantined after they were found to have attended the congregation while 12 others are said to have left the country. The state authorities have also identified 342 Indians who had attended the event, out of which nearly 200 have been quarantined.
The Uttar Pradesh government has also ordered 569 people to be quarantined for having attended the congregation, while Gujarat has so far quarantined at least 85 and a massive manhunt is underway as nearly 1,500 from the state have been found to have participated in the religious gathering.
Gujarat High Court, separately, also issued notice to the central and the state governments over the Nizamuddin congregation.
The Uttarakhand government has also identified 26 such people, but said they were yet to return from Delhi.
In Rajasthan, the government officials said 538 persons could have travelled to various parts of the state after attending the event.
At least 81 Tablighi Jamaat returnees are suspected to be in Bihar, out of which 30 have been identified, while Assam has reported four new confirmed cases of the deadly virus infection all of whom had attended the Tablighi Jamaat meet.
Amid heightened efforts to contain the pandemic, Prime Minister Narendra will also hold a video conference with all chief ministers on Thursday during which issues such as ways to contain the spread of COVID-19, movement of migrants and contact tracing of Tablighi Jamat participants are likely to come up for discussion, sources said.
The availability of essential items will also be discussed during the conference in the wake of the ongoing nationwide lockdown, which entered the 8th day on Wednesday.
In the meantime, the armed forces have made available over 9,000 hospital beds and more than 8,500 doctors and support staff across the country to deal with the rising cases of coronavirus infection, while Railways has also converted some of its coaches into isolation wards.
India is also looking at South Korea, Germany and China for procurement of cutting-edge technology and adopting best practices being followed by them in successfully containing the spread of coronavirus amid looming risk of the country entering the community infection stage of the pandemic, officials said.
Fresh cases of infection reported on Wednesday included some doctors and a police constable as well.
More than 43,000 people have died due to COVID-19 worldwide so far since December, while more than 8.6 lakh infections have been reported so far. Nearly half of the world population is currently under partial or full lockdown, taking a big toll on the economy as well.