Media playback is unsupported on your device Media caption Drone footage shows the chaos left in the gas blasts' wake, as Cindy Sui reports

A series of gas explosions in the southern Taiwanese city of Kaohsiung has killed 25 people and injured 267 others, officials say.

The blasts rocked the city's Cianjhen district, scattering cars and blowing deep trenches in roads.

The exact cause of the gas leaks is not clear, but reports say the blasts were caused by ruptured pipelines.

Images of the scene showed major fires, upturned vehicles, bodies covered in debris and streets split in two.

The explosions happened late on Thursday night, with witnesses reporting huge fireballs soaring into the air. Taiwan's premier said there were at least five blasts.

"The local fire department received calls of gas leaks late Thursday and then there was a series of blasts around midnight affecting an area of two to three sq km [one sq mile]," the National Fire Agency said in a statement.

"I saw lots of cars and motorcycles with engines all over on the road, and doctors checking if bodies were dead or alive," eyewitness Chen Guan-yuan, who was at the scene shortly after the blast, told the BBC.

"Because the explosion range is so far so it's really difficult to handle this situation immediately," Mr Chen said, adding that the blasts "caused a long-range hole, like a huge cave".

Image copyright AFP Image caption The explosions split roads in two and threw vehicles into the air

Image copyright AFP Image caption The blasts ripped through the southern city of Kaohsiung late on Thursday

Four firefighters who were investigating reports of a gas leak were said to be among the dead.

People in the area were evacuated to schools as teams battled the blazes. By Friday morning most fires were reported to have been extinguished.

Firefighters were still trying to see if people were trapped under the rubble, the BBC's Cindy Sui in Taipei reported.

The exact cause of the blasts had not yet been identified but several petrochemical companies had pipelines running along the sewage system in the district, our correspondent added.

"The cause of the gas leak is still not clear at this moment. We suspect the leaked gas could be propylene," said Economic Affairs Minister Chang Chia-chu.

Cindy Sui, BBC News, Kaohsiung

The area where the explosions happened is just a short distance from the Kaohsiung City Hall, the popular Guanghua Night Market, the Shin Kong Mitsukoshi Department Store and at least one major hotel.

Eyewitnesses and local residents reported smelling a strong gas odour about three hours before the explosions occurred. Many of them were worried and went outside.

One person wrote online that he called Kaohsiung City's hotline for residents but was told that firefighters had arrived on the scene and to go back home.

As he expressed anger to the hotline operator, he saw a large explosion. Manhole covers were blown three stories high. Many people lay injured on the street.

Another resident who lived nearby said that he thought it was an earthquake at first and then he heard something like a bomb. The electricity was cut off. He immediately woke up his wife and children and they quickly left their home.

Taiwanese fearful after pipeline blasts

Image copyright AFP Image caption Scores of people were wounded in the blasts that shot debris into the air

Image copyright AP Image caption Br Friday most fires were out as residents began to assess the devastation

One witness told AFP news agency he saw "fire soaring up to possibly 20 storeys high after a blast".

Another told Taiwan's Central News Agency that the "explosions were like thunder and the road in front of my shop ripped open".

"It felt like an earthquake," the witness said.

People had been ordered to stay home from school and work in Kaohsiung's Cianjhen and Lingya districts on Friday, local media reported.

Media playback is unsupported on your device Media caption Cindy Sui reports: ''The strength of the blast was so powerful that it tore up this entire street for about one kilometre''

Kaohsiung mayor Chen Chu wrote on her Facebook page (in Chinese): "Rescue efforts are still underway."

She urged everyone to "follow the instructions of rescue teams at the scene, and avoid standing around and watching".

"The local government has already requested [gas suppliers] CPC and Hsin Kao Gas cut off the gas supply," she added, urging residents to stay calm.

The local government has set up an emergency response centre.