An investigation has begun into a bomb explosion in the Kashmiri summer capital Srinagar, on the road to a guesthouse where the Indian prime minister, Atal Bihari Vajpayee, was staying.

No one was hurt but the explosion represents an embarrassing lapse in security during the prime minister's two-day visit.

Muslim separatist groups have called a general strike in protest at the visit.

In Srinagar, Mr Vajpayee reiterated his government's determination to combat militant separatists, but he said that Kashmir's special constitutional status , which gives it more powers than other Indian states, would not be changed.

He also denounced intolerance and said India could only work as a secular country where no religion was paramount.

Critics of Mr Vajpayee's Hindu nationalist Bharatiya Janata Party accuse it of wanting to end India's official secularism.