A woman surnamed Wang kept trying to call her husband and daughter, who were believed to be trapped in the building.

"She called me at about 6:15 p.m., but I couldn't contact her and her father anymore. She is so young," the woman cried, collapsing to the ground.

An elderly woman living in the top floor of an adjacent building smelt the smoke first and saw parts of the scaffolding falling in flames. She carried her granddaughter down to the ground along with her husband, just before the elevator stopped working.

A young woman who gave birth two months ago was believed to be trapped in the building.

"I told her on the phone to protect herself with wet towels and quilts, but couldn't contact her again," said the woman's sister.

Many residents scrambled to the roof, but the flames were too strong for helicopters to lift them off.

Shanghai people began to mourn the victims Tuesday as some laid flowers at the site of the tragedy.

"I don't live in the block. I just came to express condolences," a man said without offering his name.

Safety loopholes

The building was covered by scaffolding made of flammable nylon netting and bamboo, Chen said, adding that strong winds helped the fire spread.

Battling fires in high-rise buildings was difficult because flames could jump to nearby buildings, he said.

Experts said fire-fighting capabilities in many Chinese cities were inadequate for fires more than 60 meters above ground level. People had to help themselves in higher buildings, said Wang Wuren, a leading architect and former chief engineer of China State Construction Engineering Corporation.

"The highest aerial ladder apparatus in China is not more than 100 meters, but there are almost 1,000 buildings more than 100 meters high in Shanghai alone," Wang said.

In some big cities, fire engine access had been squeezed, leaving many sites unaccessible, Wang said.

Li Jin, deputy director general of Beijing Fire Bureau, said helicopters would be restricted by the smoke, heat, strong winds, and crowded space during the rescue process.

"According to regulations, a fire station must be set up every four to seven square kilometers, but rapid urban expansion makes it hard for fire control facilities to catch up," Li said.

Li suggested spacial and regional plans should be considered during the urban planning process to avoid further tragedies.

"Enough space should be reserved for fire control emergencies, especially around high-rise buildings," he said.

Li said Beijing had purchased a fire appliance that could extend to 90 meters high for the Olympic Games, and after the fire at the China Central Television (CCTV) headquarters in 2009, another that could reach 101 meters was ordered and would soon be put into use.

In addition, many residential buildings provided too few or ineffective safety facilities and the maintenance work was inadequate. Fire control authorities in other provinces and cities, such as Tianjin, Guizhou and Zhejiang, Tuesday started inspections of facilities in a bid to prevent similar occurrences.