Firefighters return from the warehouse area, where they were involved in rescue operations.[ZHU XINGXIN/CHINA DAILY]

At least 44 have been rescued from the debris in Tianjin Binhai New Area as of 6 pm on Friday, after blasts originating from a dangerous-chemicals warehouse killed 56 and injured hundreds.

Zhou Tian, chief of firefighting at Tianjin's public security bureau, said in a press briefing on Friday that basically all the flames have been extinguished and are unlikely to reignite as rescue continues, and sand is being used during the firefighting when water is inappropriate to douse fire caused by chemicals.

However, the city's latest press briefing on the development of the tragedy failed to address public concerns on whether dangerous chemicals were stored too close to residential communities.

Officials also refrained from answering questions if improper firefighting methods had caused more explosions after the first blast.

Zhou said rescue workers have divided the blast scene into four areas and at least 66 large rescue equipment and 600 metric tons of sand have been used to combat the fire.

Zhang Ruigang, deputy head of Tianjin Binhai New Area, said more than 110 medical experts have been transferred from downtown to support local medical staff.

At least 17,000 households of residents, 1,700 companies and 675 stores were affected in the incident.