ISTANBUL — For weeks President Recep Tayyip Erdogan has presented Turkey’s performance in handling the coronavirus as one of the world’s most successful, as he maintained strict control over information about the outbreak.

The presidential palace rolled out a carefully orchestrated propaganda campaign, ensuring reports from hospitals, grave sites and mourning relatives remained virtually absent. Doctors who spoke out on social media were reprimanded, and 410 people were detained in March for “provocative and abusive” posts.

But 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 would suggest. The city 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.