Istanbul deaths suggest a wider outbreak than Turkey admits.

Turkey has surpassed China in its number of confirmed coronavirus cases, as the tally rose to more than 90,000 by Monday, with deaths reaching at least 2,140, according to official government figures. But the true death toll may be much higher.

Data compiled by The New York Times from records of deaths in Istanbul indicate that Turkey is grappling with a far bigger calamity from the coronavirus than official figures and statements indicate. The city alone recorded about 2,100 more deaths than expected from March 9 to April 12, based on weekly averages from the last two years, far more than officials reported for the whole of Turkey during that time.

While not all those deaths are necessarily directly attributable to the coronavirus, the numbers indicate a striking jump in fatalities that has coincided with the onset of the outbreak, a preliminary indicator that is being used by researchers to cut through the fog of the pandemic and assess its full toll in real time.

The government maintains that it acted swiftly, stopping flights and border crossings from five of the most affected countries in February and closing schools, restaurants and bars in mid-March when the first case of infection was confirmed.