NEW DELHI —The Election Commission of India, long regarded as the guardian of the world's largest democracy, is facing scrutiny after a newspaper investigation alleged impropriety during a large-scale voter-roll revision.

According to an Indian Express report last week, some key decisions linked to the contentious revision exercise were likely taken without the approval of two of the three election commissioners.

The ECI, a constitutional body, has rejected the allegations, saying all its decisions were unanimous and legally valid.

Opposition parties have long raised doubts about the nationwide revision, which has seen millions of names removed from voter rolls, saying it benefits Prime Minister Narendra Modi's ruling party.

The English-language daily reported that the poll body had been riven by internal disagreements since the so-called Special Intensive Revision (SIR) of the voter lists started last year.