Police officials on Tuesday claimed the three men and a woman wanted to kill Chief Minister Narendra Modi for fuelling the slaughter of hundreds of Muslims in 2002.
"Police had intelligence inputs that they were in town to kill the chief minister. All four were killed in an encounter early this morning," one security official said.
Security forces said two of the dead were Pakistanis, but declined to say how they knew that. Investigators were trying to determine which rebel groups the four belonged to.
The four were intercepted in a car near the airport in Ahmadabad, Gujarat's main city. Two pistols and one AK-56 assault rifle were recovered, police said.
Linked to riots
Police say they have foiled several plots to kill Modi - the hardline leader of the Hindu-nationalist Bharatiya Janata Party government in Gujarat - over the past two years.
Violence flared anew in 2002 with the deaths of 59 Hindus following a mob attack on a train carrying extremist Hindu activists.
More than 1000 people, most of them Muslims, were killed in subsequent rioting in India's worst religious strife in a decade. Non-government groups put the death toll at more than 2500.