Indian election officials have begun counting votes that were cast in the country's mammoth general elections.

The count began Thursday morning and was expected to conclude by the evening. Voters cast ballots on some 40 million electronic voting machines.

Half a dozen exit polls showed Prime Minister Narendra Modi and his Hindu nationalist Bharatiya Janata Party remaining in power for another five years.

In the world's largest democratic exercise, some 900 million people were registered to cast ballots for 542 seats in India's lower house of Parliament in seven phases of polling staggered over six weeks.

The election has been seen as a referendum on Modi, whose economic reforms broadly haven't succeeded but whose popularity as a social underdog in India's highly stratified society has endured.