Four held over Shanghai blaze that left 53 dead

Chinese police detained four people for allegedly sparking a fire in a Shanghai high-rise that killed 53 people, as anxious relatives searched desperately for news of missing loved ones.

The blaze raged for several hours on Monday, causing panicked residents to jump from the inferno or seek refuge on rickety construction scaffolding surrounding the building as thick smoke spread above China\'s commercial hub.

Police were holding four people in connection with the blaze, the municipal government said in a statement, adding that an initial investigation blamed the fire on unlicensed welders.

"I\'ve been waiting since last night. I don\'t know when I can see my mother," Yang Bo, 32, told AFP, after scouring hospitals in the area for his 65-year-old mother.

Yang had sped to the city from neighbouring Jiangsu province after hearing of the fire on Monday.

He said he was joined by angry crowds at each hospital, where relatives demanded information about their loved ones but were turned away from morgues, with officials saying they must first obtain government permission to enter.

The 28-storey building -- in one of the most densely populated districts of the city of nearly 20 million people -- was under renovation when the fire broke out in mid-afternoon.

The fire was the city\'s worst in years, the Shanghai Daily said, without giving further details.

Deadly fires are common in China due to lax observation and enforcement of fire safety measures.

The blaze started on the scaffolding\'s 10th storey, and plastic construction sheeting covering the building helped fuel the fire, Zhu Zhixiang, a senior Shanghai fire official, told CCTV state television.

"The building was surrounded by scaffolding covered in a lot of flammable sheeting and plywood boards that caused the fire to spread to a large area in a very short time. The wind was strong and intensified the situation," Zhu said.

Photos published by state media showed residents clinging to the scaffolding to escape the flames.

Hu Zhenqing, 60, who lived on the 20th floor, told the Global Times newspaper that he heard desperate cries as he and his wife fled the building.

"It was gut-wrenching -- then we saw a woman jump from high above. We didn\'t see where she landed, but I don\'t think she made it," Hu said.

At least 53 people died and 70 were being treated for injuries, the municipal government said.

Chinese authorities will thoroughly investigate the fire and punish anyone responsible, Public Security Minister Meng Jianzhu was quoted by Xinhua as saying.

A resident of the block, identified only by her surname Zhao, told Xinhua she had filed complaints about construction workers dropping cigarette butts around the building.

"Such a horrible scene belongs in novels, not real life. I could hardly believe my eyes," she said.

The building was an apartment block for teachers, according to state media reports, which said most were retired.

Yang Bo wound up looking for his mother at an indoor sports centre being used as a temporary evacuation site for residents of the building and adjacent structures.

Relatives crowded around lists of the missing and hospitalised that were posted on walls at the evacuation centre. The "missing" list said the whereabouts of more than 50 people remained unknown.

However, no official list of the missing was released to the public.

"All the staff here ask me to wait. How long should I wait?" Yang said.

A total of 156 families lived in the building, municipal officials said.\\

The renovations were among thousands of projects that began after Shanghai lifted a moratorium on major construction in the city centre during the six-month World Expo, which ended on October 31.