The BBC said it was fully cooperating with the Income Tax surveys.
At least 10 senior employees of the British Broadcasting Corporation (BBC) in Delhi have not gone home since the Income Tax department launched a "survey" at their Indian offices, sources have said, as the operation entered its third day on Thursday.
Officials gathered financial data from staffers and made copies of documents of the news organisation in an action that comes weeks after the broadcaster aired a two-part documentary "India: The Modi Question" on Prime Minister Narendra Modi and the 2002 Gujarat riots.
A BBC staffer in Delhi said they were broadcasting their news like usual and many employees were working from home.
The operation that began at the BBC offices in Delhi and Mumbai around 11:30 am on Tuesday has clocked more than 45 hours now, officials said.
Authorities had said on Wednesday that the exercise would continue for some more time, saying the "exact time frame to call the operation closed rests entirely on the teams on the ground".
The survey is being carried out to investigate issues related to international taxation and the way funds are transferred between different arms of a multinational corporation, officials have said.
The survey teams are seeking answers on financial transactions, the company structure and other details about the news company, and are copying data from electronic devices as part of their task of collecting the evidence, tax officials had said.
Opposition parties have denounced the tax department's action against the London-headquartered public broadcaster, terming it a "political vendetta" in response to the documentary on PM Modi. The ruling BJP has accused the BBC of "venomous reporting" and being "most corrupt".
While there has been no official statement from the Income Tax department on the action, the BBC has said it was cooperating with the authorities.
The Supreme Court last week dismissed a plea seeking the imposition of a complete ban on the BBC in India in the wake of the controversial documentary, terming the petition "entirely misconceived" and "absolutely meritless".
Another set of petitions challenging the government's decision to block the documentary's links on social media platforms will be heard in April. On January 21, the government issued directions to block multiple YouTube videos and Twitter posts sharing links to the documentary.
(With inputs from agencies)