Income tax officials conduct a search at BBC office in New Delhi

NEW DELHI - India's financial crime-fighting agency has opened an investigation into alleged violations of foreign exchange rules by the BBC, a source told Reuters on Thursday, months after tax officials searched the broadcaster's Mumbai and Delhi offices.

The tax raids in February had come close on the heels of the release of a BBC documentary about Prime Minister Narendra Modi's leadership of the state of Gujarat during riots in 2002. At least 1,000 people were killed in the riots, most of them Muslims.

The latest investigation is being conducted by the Enforcement Directorate (ED) under India's Foreign Exchange Management Act. The agency issued a notice to the BBC in March and questioned some employees earlier this month, said the source, who declined to be named citing the sensitivity of the matter.

An ED spokesperson did not immediately respond to calls and a text message seeking comment. The BBC did not immediately respond to an email seeking comment.

The Foreign Exchange Management Act, 1999, is a civil law and the ED conducts investigations into suspected contraventions of it to "adjudicate and impose penalties" on those found guilty, it says on its website.

British Foreign Minister James Cleverly, during a visit to New Delhi in March, raised the BBC tax searches with his Indian counterpart.

Relations between India and Britain, who are working to seal a delayed free-trade agreement, have also been strained by protests outside the Indian High Commission in London last month.

India on Wednesday asked Britain for increased monitoring of UK-based supporters of a Sikh separatist movement following a "breach of security" at the High Commission. The British government said this week they were working to "review security and make changes to ensure the safety of its staff".