A Pakistan International Airlines Airbus A320 flying from Lahore has crashed in the densely populated Model Colony residential area of Karachi.
Flight PK8303, carrying 91 passengers and eight crew, crashed on approach to the busy Jinnah International Airport.
The provincial health minister said at least 11 people had died, but a far higher toll is feared. At least two passengers are confirmed survivors.
The pilot had reported loss of engines and then issued a Mayday.
TV footage showed rescue crews combing through debris strewn across the streets of Model Colony, 3.2km (two miles) north-east of the airport. A number of houses have been destroyed.
The plane had lost contact with air traffic control just after 14:30 local time (09:30 GMT), an airline spokesman said.
Eyewitness Mohammed Uzair Khan told the BBC he had heard a massive sound and went outside his home.
“Almost four houses were completely collapsed, there was so much fire and smoke,” he said. “They are almost my neighbours, I can’t tell you what a horrible thing it was.”
Dr Kanwal Nazim told BBC Urdu she heard people screaming and saw clouds of black smoke rising from the three houses adjoining a mosque.
The chief minister of Sindh, the province where the plane crashed, has declared an emergency in all of Karachi’s hospital.
The cause of the crash is yet to be confirmed. PIA chief executive Air Vice Marshal Arshad Malik said the pilot had told traffic control that the plane was experiencing “technical difficulties”.
Pakistan’s Dunya News said it had obtained a recording of the conversation, also posted on monitoring website liveatc.net.
In it the pilot says they have “lost two engines”. Several seconds later he calls “Mayday, Mayday, Mayday” and there is no further communication.
Bank of Punjab president Zafar Masud was among the passengers and had survived the crash, a Sindh provincial government spokesman said. The other survivor was named as Muhammad Zubair.
A senior journalist at TV channel 24 News, Ansar Naqvi, was also listed on the passenger manifest.
Pakistan’s Prime Minister Imran Khan said he was “shocked and saddened” by the crash, promising an immediate investigation.
The crash comes just days after the country began allowing commercial flights to resume after a coronavirus lockdown.
Pakistanis across the country are preparing to celebrate the end of Ramadan, with many travelling back to their homes in cities and villages. -BBC