Wang Wei has been fighting fires for 10 years, but "never before" has he seen a blaze as intense as the one that gutted the 28-story residential building in downtown Shanghai on Monday, killing 58 people.

?Mourners lay flowers at the entrance of the gutted apartment block on Wednesday.

"When we arrived at the scene, the entire building was engulfed in flames and the bamboo scaffolding and the nylon net over it were burning furiously," Wang recalled.

"Once we reached inside the building, it seemed as if every floor and every household was on fire. Our efforts to save lives were hindered by the intense heat and smoke."

Wang, director of Pengpu squadron of the Shanghai Firefighter Brigade, is one of the 1,300 firefighters who battled the blaze, one of the worst in Shanghai's history, backed by at least 120 fire engines.

It took them four hours to put out the fire in the building, which was home to some 150 households.

The fact that the building was burning from all sides and from bottom to top made it tougher for the firefighters, Wang said, adding that the dry weather and wind helped the fire spread quickly.

Due to zero visibility caused by thick smoke, Wang and his colleagues had to feel their way up the stairs in search of survivors.

"We tried our best to protect survivors while escorting or carrying them down the stairs. Many of my colleagues gave their respirators to the survivors and acted as human shields from falling balls of fire," he said.

Wang and his colleagues climbed up and down the burning building at least 10 times.

Wang alone saved five people during the operation, which continued into Tuesday morning, long after the fire was extinguished.

Two comrades from his squadron saved 13 people trapped on top of the building, after an attempt to fly them to safety in a helicopter was thwarted by the heavy smoke.

A firefighter from the squadron fainted due to fatigue, only to rejoin the operation minutes later, said Wang.

"None of us could afford to rest. Saving as many people as possible was the single thought on our minds.

"In a situation like this, the most important thing for us is to remember how we got in, because we have to know the way out," he added.

Firefighters saved a total of 160 people from the building, according to official statistics.

Wang, who battled for eight consecutive days to save survivors of the devastating Sichuan earthquake in 2008, said he cannot help feeling sad about the death toll from the fire.

"It's tragic, but tackling high-rise blazes is a worldwide headache," he said. "We should work more on safety measures in order to prevent similar disasters in the future."