An underground electrical fire in central London Wednesday sent flames and smoke billowing out of manhole covers on a busy main road, leading to the evacuation of thousands of office workers and students from nearby buildings.

Witnesses reported “chaos” as flames and acrid smoke shot out into the three-lane road in Kingsway, Holborn while others said they “struggled to breathe.” More than 2,000 people were evacuated, Sky News reported.

Approximately 70 firefighters tackled the blaze, which was eventually brought under control. The London Fire Brigade said there were no reports of injuries and that crews were going to be working through the night to extinguish the fire, the BBC reported.

A representative from the LFB told the BBC that the fire started in a large service duct that carries electrical cables and gas and water pipes beneath the street. The dramatic flames coming out of manhole covers were due to the subsequent rupture of a gas pipe.

Nicola Foxfield, 29, told Sky News: "I could smell burning in the air. As I got closer I could see fire engines everywhere.

"Then I could see loads of thick, brown smoke rising off the road. It's chaos and fire engines are coming from every direction and there are so many people around."

UK Power Networks told the BBC that 1,900 customers were left without electricity, and that it had managed to restore power to most of them.

Shows at nearby West End theatres were canceled.