ISLAMABAD — A passenger jet that officials suspect veered off course in monsoon rains and thick clouds crashed into hills overlooking Pakistan’s capital Wednesday, killing all 152 people on board and scattering body parts and twisted metal far and wide.

The Airblue jet’s crash was the deadliest ever in Pakistan, and just the latest tragedy to jolt a country that has suffered numerous deaths in recent years due to al-Qaida and Taliban attacks. At least two U.S. citizens were on the plane, which carried mostly Pakistanis.

The plane left the southern city of Karachi at 7:45 a.m. for a two-hour flight to Islamabad and was trying to land when it lost contact with the control tower, said Pervez George, a civil aviation official. Airblue is a private airline based in Karachi, Pakistan’s largest city.

The aircraft, an Airbus A321, crashed some 15 kilometers from the airport, scorching a wide stretch of the Margalla Hills, including a section behind Faisal Mosque, one of Islamabad’s most prominent landmarks. Twisted metal wreckage hung from trees and lay scattered across the ground. Smoke rose from the scene as helicopters hovered.

The exact cause of the crash was not immediately clear, and rescue workers were seeking the “black box” flight data recorder amid the wreckage. But Defense Minister Chaudhry Ahmed Mukhtar said the government did not suspect terrorism.

Rescue workers and citizen volunteers were hampered by the rain, mud and rugged terrain. The crash was so severe it would have been nearly impossible for any of the 146 passengers and six crew members to survive, rescue officials said.

“There is nothing left, just piles and bundles of flesh. There are just some belongings, like two or three traveling bags, some checkbooks, and I saw a picture of a young boy. Otherwise everything is burned,” rescue worker Murtaza Khan said.

As the government declared Thursday would be a day of mourning and condolences poured in from the U.S., Britain and other nations, hundreds of people showed up at Islamabad’s largest hospital and the airport seeking information on loved ones.

They swarmed ambulances reaching the hospital, but their hopes fell as rescue workers unloaded bags filled with body parts. A large cluster of people also surrounded a passenger list posted near the Airblue counter at the airport.

“We don’t know who survived, who died, who is injured,” said Zulfikar Ghazi, who lost four relatives. “We are in shock.”

Mirza Ahmed Baig rushed to the hills after hearing that the plane carrying his brother had crashed. He wept amid the chilly weather, criticizing the rescue effort as too little and too lax.

“I’m not satisfied at all on the steps the government is taking,” Baig said.

As of Wednesday night, when rescue work was suspended till the morning, 115 bodies had been recovered, federal Information Minister Qamar Zaman Kaira said. DNA tests would be needed to identify most of them, he said.

U.S. Embassy spokesman Richard Snelsire confirmed that at least two American citizens were on board, but he declined to provide any further information on their identities or links to Pakistan.

Witnesses said the plane appeared to be flying very low and that it seemed unsteady in the air.

“The plane had lost balance, and then we saw it going down,” Saqlain Altaf, who was on a family outing in the hills when the crash occurred, told Pakistan’s ARY news channel.

The Pakistan Airline Pilot Association said the plane may have strayed off course, possibly because of the poor weather. Several officials noted the plane seemed to be an unusual distance from the airport, which was some 9 1/2 miles (15 kilometers) away.

“It should not have gone so far,” said Air Vice Marshal Riazul Haq, deputy chief of the Civil Aviation Authority. “We want to find out why it did.”

Raheel Ahmed, a spokesman for the airline, said the cause of the crash would be investigated. The plane had no known technical issues, and the pilots did not send any emergency signals, Ahmed said. Airblue flies within Pakistan and to the United Arab Emirates, Oman and the United Kingdom.

Airbus said it would provide technical assistance to the crash investigators. The aircraft was initially delivered in 2000, and was leased to Airblue in January 2006. It accumulated about 34,000 flight hours during some 13,500 flights, it said.

The only previous recorded accident for Airblue, a carrier that began flying in 2004, was a tail-strike in May 2008 at Quetta airport by one of the airline’s Airbus 321 jets. There were no casualties and damage was minimal, according to the U.S.-based Aviation Safety Network.

Other Pakistani airlines have come under international scrutiny due to safety concerns.

In 2007, the European Union temporarily banned flights in its airspace of most of the aircraft operated by Pakistan’s national carrier, Pakistan International Airlines, because of concerns over the age of the aircraft and poor maintenance. The bloc lifted the ban later that year after the airline took action to comply with safety standards.

The last major plane crash in Pakistan was in July 2006 when a Fokker F-27 twin-engine aircraft operated by PIA slammed into a wheat field on the outskirts of the central Pakistani city of Multan, killing all 45 people on board.

In August 1989, another PIA Fokker, with 54 people onboard, went down in northern Pakistan on a domestic flight. The plane’s wreckage was never found. In September 1992, a PIA Airbus A300 crashed into a mountain in Nepal, killing all 167 people on board.

The Airbus 320 family of medium-range jets, which includes the A321 model that crashed Wednesday, is one of the most popular in the world, with about 4,300 jets delivered since deliveries began in 1988.

Twenty-one of the aircraft have been lost in accidents since then, according to the Aviation Safety Network’s database. The deadliest was a 2007 crash at landing in Sao Paolo by Brazil’s TAM airline, in which all 187 people on board perished, along with 12 others on the ground.

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AP Aviation Writer Slobodan Lekic in Brussels, as well as Associated Press writers Ashraf Khan in Karachi and Zarar Khan, Nahal Toosi and Sebastian Abbot in Islamabad, contributed to this report.