Indian police have arrested four men, including an aide of the leader of an armed group accused of several bomb blasts, who they said could be plotting an attack ahead of elections starting next month.

Zia-Ur-Rahman, alias Waqas, was arrested on Saturday in Ajmer in the western state of Rajasthan, the second major blow for the Indian Mujahideen after the capture of founder leader Yasin Bhatkal in Nepal last year.

Three other suspected members of the group were also arrested with a large quantity of explosives, police said.

Waqas, who police said was a Pakistani national, was wanted for bomb blasts in Mumbai, Pune and Hyderabad over the past several years, officials said.

The Indian Mujahideen group has been accused of dozens of bomb attacks over recent years. The group is also suspected of being behind an attack on a rally by prime ministerial candidate Narendra Modi last October that killed six people and wounded more than 80.

"Their target was a terror strike," S N Srivastava, a top police official in New Delhi, told a news conference on Sunday, but declined to comment when asked if Narendra Modi was being targeted, saying they needed further investigation.

"Any important event, including elections, could be targeted."

Interior Minister Sushilkumar Shinde said the arrest of Waqas was a great success as he was a crucial link to the group.