Smoke rises over damaged containers and cars after a huge explosion rocked the port city of North China's Tianjin, August 13, 2015. [Photo by Xu Jingxing/ China Daily]

Tianjin fire department have confirmed that at least 11 firefighters have been killed, with another 30 still missing, as they were hit by secondary blasts during the rescue operation in the explosions at the warehouses of Tianjin port on Thursday.

The first explosion at a warehouse of chemical materials came at around 11:20 pm on Wednesday, followed by a number of blasts, the new office of the Tianjin Binhai New Area said on its official blog.

The secondary blast caused heavy casualties to the firefighters who were carrying out search and rescue work and fighting the fire, leaving at least 11 dead and another 30 missing, according to the fire department under the Tianjin police.

The blast also destroyed seven to eight fire engines, said Beijing News. Another 33 firefighters have been hospitalized with injuries, according to police.

The firefighters have received several tributes on the country’s social media, with a number of posts praising the bravery and courage displayed by the firefighters early on Thursday.

"As others were retreating from the blast site, they dashed in. It was the most courageous reverse motion in the world," wrote Sina Weibo user Xiaocugang zz.

Many firefighters had tears in their eyes as they tried to find survivors and carry the bodies out the blast scene, some of the bodies were part of their ranks only hours ago.

The blast was the most severe he had ever seen in his whole career as a fire fighter, said a firefighter with the fire department of Tanggu New Port, who would only provide his surname as Lu.

"We first went into the blast scene at around 12 pm, and we have been in and out three or four times," said the native of Chongqing who has been serving the fire department for more than four years.

Lu and his squad were standing outside the blast site as the special work group from Beijing was still evaluating the blast scene.

"We brought some injured person out. It was total destruction inside. We were still trying to extinguish the fire one hour ago," he said.

He said he and his fellow soldiers were used to responding first to orders.

"We have the best equipment and have received the best training. If we do not go, who else can," he said.