NEW DELHI: India has reported 28 positive cases of coronavirus so far, which includes 16 Italian tourists, Union health minister Harsh Vardhan said on Wednesday and announced that all international passengers will henceforth be screened at airports for the disease.Earlier, travellers from only 12 countries were being screened at the airports.Vardhan held a meeting with Delhi health minister Satyendra Jain and civic body officials on Wednesday and urged them to augment facilities of isolation wards in city hospitals if more cases of coronavirus gets recorded."We have to work as a unit to combat the COVID-19 threat to the nation. A coordinated, collective effort in a mission mode is required," he said at the meeting.Giving a breakup of those who tested positive for the virus, the Union health minister said of the total 28 COVID-19 cases in India, one is a 45-year-old man from Delhi's Mayur Vihar and six are his relatives from Agra whom he recently visited. They are all being treated at the Safdarjung hospital.A 24-year-old man from Hyderabad has also tested positive for coronavirus and has been isolated. Besides, 16 members of a tourist group from Italy and their Indian driver have been found infected with the virus.While an Italian man and his wife are being treated at Jaipur's SMS Hospital, 14 members of the group and their Indian driver have been quarantined at the ITBP camp in Chhawla.According to health ministry officials, the Italian tourists wanted to go back to their country after the first person in their group tested positive in Jaipur, but authorities advised them to stay in India. Three coronavirus patients reported in Kerala earlier have already been discharged.The ministry also said that two cases with high viral load have been detected in Telangana.Vardhan said that so far, 5,89,000 people have been screened at airports, over 15,000 at major and minor sea ports, around 10 lakh at borders with Nepal and around 27,000 were currently under community surveillance.As part of the country's preparedness for containing the spread of the disease, the Union health minister said that all the foreign nationals, and not just those from 12 countries listed earlier, will henceforth be screened for COVID-19 at 21 designated airports.Addressing the media, he said the government has adopted a cluster approach, as a part of which health authorities will check and sensitise every household within 3 km-radius of the house of the infected person, to prevent community spread of the virus.Vardhan said that at present, 15 laboratories in India are conducting tests for coronavirus. Nineteen more laboratories are being established, he said, adding seven to eight labs started functioning on Tuesday and rest will be made operation by Wednesday.Health ministry officials said during contact tracing procedure, the ministry's Integrated Disease Surveillance Programme (IDSP) have identified 66 people who had come in contact with the Delhi man who has been tested positive for coronavirus, while 88 people who had come in contact with the 24-year-old Hyderabad man have been identified.Vardhan further said the government intends to set up a laboratory in Iran so that Indians there can be tested for possible exposure to novel coronavirus before being brought back. An estimated 1,200 Indians, mostly students and pilgrims, are in Iran currently.While coronavirus infection is showing signs of receding in China with 38 new fatalities, taking total number of deaths to 2,981, in Iran, over 2,000 coronavirus cases and 77 deaths have been reported."If the Iranian government lends its support, a testing facility could be set up there as well, so that Indians there can be tested before they can be brought back," the Union health minister said.One scientist from the National Institute of Virology (NIV) in Pune has been sent to Iran while three more from the Indian Council of Medical Research (ICMR) will leave at 4 pm on Wednesday to check the feasibility of setting up a laboratory there for conducting coronavirus test.Vardhan urged people to avoid crowded places and physical contact with people.Responding to a question over shortage of masks across the country, the Union health minister said, "We have ensured that the export of N95 masks and personal protective equipment, etcetera, are banned and taken care of. The ministry has taken adequate measures to ensure there is no scarcity of these."He urged the states and Union Territories to strengthen core capacities for disease preparedness and response like surveillance, laboratory diagnosis, hospital preparedness, logistic management, capacity building and risk communication.Vardhan also said that the states need to identify isolation facilities, to accommodate confirmed and suspected cases if and when identified in each district, as well as logistics requirement and to enhance community awareness through print, electronic and social media.