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. 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.

The government declared a day of mourning today.