Pakistan is observing a day of national mourning following the country's worst-ever air disaster.

巴基斯坦宣布进入一天国家哀悼日以纪念其历史上最严重的空难。

An Airbus A321 crashed as it was about to land in the capital Islamabad, killing¹ all 152 people on board.

The domestic flight from the southern city of Karachi was operated by the private Pakistani airline Airblue, which has a good safety record.

There is no word on the cause of the crash. It happened in heavy monsoon²（季风，雨季） rain and poor visibility.

The plane - with 146 passengers and six crew on board - was flying at an extremely low level before crashing into the Margalla hills north of the capital, eyewitnesses³ said.

Prime Minister Yousuf Raza Gilani declared Thursday a day of national mourning and ordered flags to fly at half-mast（桅杆，柱） across the country.

Information Minister Qamar Zaman Kaira said 115 bodies had been recovered, but bad weather and difficult terrain⁴（地形，地势） had hampered⁵（阻碍，限制） recovery efforts.

Airline response

Passengers' remains⁶ were badly damaged in the crash and DNA⁷ tests would be used to identify the victims, he told reporters.

Aamir Ali Ahmed, a senior city government official, told Reuters news agency: "It's a very difficult operation because of the rain. Most of the bodies are charred⁸（烧焦的） ."

Rescue worker Dawar Adnan told Associated Press from the crash site: "I'm seeing only body parts. This is a very horrible scene."

So far, only 46 bodies have been identified.

Two Americans were among the victims, a US embassy spokesman said, but gave no further details.

Officials say investigators⁹ are still looking for the flight data recorder, denying earlier reports that the "black box" had been found.

The BBC's Aleem Maqbool in Islamabad says that many flights on the popular route from Karachi to Islamabad have been cancelled in recent days because of the bad weather.

There are already serious questions being asked about why this plane was allowed to fly, and about whether this tragedy could have been averted¹⁰, our correspondent adds.

There were also complaints（投诉，抱怨） about the response of Airblue.

"We didn't get information," says Zulfiqar Qadri, who lost a family member. "They just put a list of dead passengers in our hands."

Airblue spokesman Raheel Ahmed told reporters that the crash had been "an extremely tragic¹¹ incident" and the plane had no history of technical problems.

It was leased（租用） by Airblue in January 2006 and had accumulated about 34,000 flight hours.