More than 70 firefighters responded to a huge fire at the famous Camden Market early Monday morning, the city's fire brigade said.
London Fire Brigade asked public to avoid the area and roads are closed.
Metropolitan Police said firefighters were already on the scene when they arrived.
"It is unknown at this stage if any persons are injured, we await update," police said in a statement.
The market at Camden Lock sustained major damage in a fire in 2008 and it remained closed for months during reconstruction.
There are more than 1,000 shops and stalls at the market in North London, which is a major attraction for locals and tourists.
