A Pakistan International Airlines (PIA) passenger plane flying from Lahore has crashed into a residential area of Karachi, killing at least 57 people.
The pilots of flight PK8303, an Airbus A320 carrying 91 passengers and eight crew, were attempting to land at the city's Jinnah International Airport.
The plane had attempted one landing but as it went round again lost its engines and issued a mayday call.
At least two passengers are confirmed to have survived the crash.
It has yet to be confirmed but here is what we know so far.
Flight PK8303 was approaching Jinnah International Airport at about 14:30 local time (09:30 GMT). It had been given permission to land but the pilots decided to abort and go around for a second attempt.
The reason is not yet known, but one civil aviation official told Reuters the plane may have been unable to lower its undercarriage. Images posted on social media appeared to show scorch marks under both engines, with no undercarriage visible on approach.
Purported audio of the conversation between air traffic control and a pilot for the second attempt was published by Pakistani media outlets, in which the pilot is heard saying the plane has "lost engines". An air traffic controller asks whether it is going to carry out a "belly landing", to which the pilot replies "mayday, mayday, mayday" - the final communication from the plane.
Investigators will try to retrieve the so-called black box recorders to help determine the cause. A committee of investigation has already been set up.
PIA said the plane had joined the fleet in 2014 and passed its annual airworthiness inspection last November.
The crash came just days after Pakistan 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.
The plane was only just short of the runway perimeter when it struck houses in the Model Colony residential area. TV footage showed rescue crews combing through debris strewn across the streets of the densely populated zone. A number of cars were set on fire.
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."
Another resident, Dr Kanwal Nazim, said she heard people screaming and saw clouds of black smoke rising from the three houses adjoining a mosque.
Local health officials at two hospitals, the Jinnah and Civic hospitals, gave death tolls to the BBC and Pakistani media, adding up to 57 confirmed deaths. But it was not clear how many of the dead were passengers and how many residents on the ground.
Zafar Masud, president of the Bank of Punjab, was among the passengers who survived the crash, a provincial government spokesman said. The other known 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.
Pakistan has a chequered aviation safety record, including a number of airliner crashes.
In 2010, an aircraft operated by private airline Airblue crashed near Islamabad, killing all 152 people on board - the deadliest air disaster in Pakistani history.
In 2012, a Boeing 737-200 operated by Pakistan's Bhoja Air crashed in bad weather on its approach to land in Rawalpindi, killing all 121 passengers and six crew.
And in 2016, a Pakistan International Airlines plane burst into flames while travelling from northern Pakistan to Islamabad, killing 47 people.
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