NEW DELHI: Indian tax officers searched the BBC's offices in New Delhi and Mumbai for a second day on Wednesday, two sources said, as controversy swirled over a BBC documentary critical of Prime Minister Narendra Modi's role in deadly riots two decades ago.

The searches resumed Wednesday morning after they went on until late in the night on Tuesday, a government source and a source in the BBC's New Delhi office told Reuters.

India's Income Tax Department has declined to comment on the reason for the search. The sources declined to be identified due to the sensitivity of the matter.

The government last month blocked the documentary that focuses on Modi, a Hindu nationalist, during his time as chief minister of Gujarat state when Hindu-Muslim violence erupted in 2002.

At least 1,000 people were killed in the riots, most of them Muslims. Activists have put the toll at more than twice that number.

The government says the documentary, "India: The Modi Question", aims to push what it calls a discredited narrative, arguing that it is "biased, lacked objectivity" and showed a "continuing colonial mindset".

The BBC has stood by its reporting for the documentary. It said on Tuesday it was cooperating with Indian tax officials, and hoped to have the situation "resolved as soon as possible".

Media organisations in India have slammed the search.

"We demand that this intimidation be stopped and journalists are left to do their jobs without fear or favour," the Mumbai Press Club said in a statement.

An editorial in the Indian Express newspaper said the government's action "smacks of bullying".

India ranks low on the World Press Freedom Index released by Reporters Without Borders, falling eight places last year to No. 150. The government has said it does not agree with the conclusions drawn by the index.