Authorities said all 84 passengers and 10 crew members died on the US-built C-130 aircraft.

"There were four apartments on each floor. Thirty-six apartments burned completely," Amir Rasouli, 24, said tearfully at Hazrat Rasoul Akram Hospital, where he learned his cousin was among the dead. "They managed to evacuate most of the residents, but my cousin was not lucky enough."

Iranian news agencies said the pilot reported engine trouble shortly after taking off from Mehrabad International Airport in southwestern Tehran. The aircraft was circling back for an emergency landing when its wing struck the building in the Towhid complex, one of many medium-rise concrete residential buildings adjacent to the airport.

The complex was reserved for military families, many of whom were home at the time.

"I was in my room when I heard a terrible explosion from the block next to us," said Mitra Aslani, 16, who like all students in Tehran stayed home from school on Tuesday because of an air pollution alert.

"Then there was fire on that block," she said.

State news agencies said police at the scene found several children among the dead. "Some people were throwing themselves out of windows to escape the flames. I saw two die like that," one policeman told the Reuters news agency.

Maysam Kamrava, whose leg was broken during the crush of people rushing out of the burning building, was among about 90 people injured in the incident.

"He is all right, but only God knows how shocked we are," said his mother, Manijeh Kamrava, 29, in the crowded emergency room at Hazrat Rasoul. "I heard a terrible explosion, and after a few seconds I heard people shouting, 'Fire!' We rushed to the stairs, which were packed with smoke. I lost my son, Maysam. A few minutes later the firemen came and helped us out of the building."

Rescue crews and bystanders carried away the wounded in blankets,. but riot police forced back distraught neighbors and relatives who tried to push past an iron gate to look for survivors.

Reporters who arrived to cover the disaster wept when they realized many of the dead were colleagues. State television played mournful music as it broadcast images of people killed in the crash.

"I was supposed to be on the plane as well, so I don't know whether to be happy or sad," a journalist from the ISNA student news agency told Reuters.

The plane was bound for the port city of Chabahar on the Gulf of Oman, where Iran's military was conducting military exercises. It took off at about 1:35 p.m. from the military section of the airport.

Mehrabad, an aging but convenient airport, has remained open despite the completion last year of the much larger Imam Khomeini International Airport, about 30 miles south of Tehran.

The cause of the crash was not reported, but state television said officials had ruled out sabotage. There have been three major fatal aircraft accidents in Iran since 2002.

News reports said the Lockheed C-130, a four-engine turbo-prop, may have been acquired from the United States when Iran was a U.S. ally and ruled by Shah Mohammad Reza Pahlavi. The monarchy was overthrown by the 1979 revolution that established an Islamic state.

U.S. trade sanctions against Iran have led to chronic shortages of aircraft spare parts. The Bush administration this year held out the possibility of lifting the sanction on airline parts as a bargaining chip in negotiations over the future of Iran's nuclear program.

"We see lots of airplanes landing in the airport every day," said Sadegh Jalaliyan, who noticed the C-130 while smoking a cigarette in the yard of the dairy factory south of the airport where he works. "I immediately recognized something was wrong with it. It was unusually low.

"I shouted to my friends and showed them the plane. Then there was a terrible explosion and a huge column of thick smoke."