The death toll from the oil pipeline explosions in the coastal city of Qingdao has risen to 44, with 166 others injured, according to local authorities.
Of the 166 injured, eight have life-threatening injuries and 57 are in critical condition.
The accident happened around 10:30 a.m. in Huangdao District. Workers were repairing the petroleum pipeline, which was leaking oil at around 3 a.m., according to Qingdao government's publicity office.
President Xi Jinping and Premier Li Keqiang urged rescuers to make every effort to search for and save those injured or missing.
State Councilor Wang Yong arrived at the scene to guide the rescue work and comfort the injured.
The pipeline belongs to China Petrochemical Corporation, also known as Sinopec Group, the country's largest oil refiner.
The 176-km pipeline links oil depots in Qingdao with Weifang, home to several petrochemical plants, in Shandong province.
With total investment of 1.3 billion yuan ($210 million), the pipeline went into operation in August. It has an annual transportation capacity of 15 million metric tons, Xinhua News Agency reported.
The company shut the pipeline down at around 3:15 am, but oil flowed onto the ground and even into the sea through a sewer pipe.
The exact cause of the explosion is still being investigated, the local government said.
Oil that leaked from the pipeline covered a ground area of about 1,000 square meters and also polluted about 3,000 square meters of sea, the local authority said.
Two containment booms were put up to prevent the spill from spreading. The oil that leaked into the sea also caught fire but this was put out.
A China Daily reporter saw debris scattered around the scene, which is close to the coast. Some well lids had been blown off.
TV footage and pictures show the blast left a deep trench in the ground and overturned a truck. Some vehicles were destroyed and almost buried by earth, cement and other debris.
Many windows were broken near the scene, causing injuries.
Environmental monitoring showed that the concentration of toxic materials in the air at the scene complies with the national standard, the Qingdao government said on its micro blog.
The exit on the bridge leading to Huangdao island was closed temporarily and only emergency vehicles were allowed to enter.
The National Health and Family Planning Commission sent a team of six experts, including two specializing in burns and two specializing in life-threatening cases, to Qing-dao to help treat the injured.
The possibility of terrorist attacks has been ruled out, the local government said.
The accident scene is far from other chemical plants and military installations, an online post by the local government stated.
A source at Sinopec headquarters told China Daily the company held an emergency meeting, and a working team has been sent to the scene.
A Sinopec employee said several subsidiary companies are taking part in the rescue operation.