A government surveillance agency had detected 300 active mobile phones at a suspected militant camp in Pakistan that India says its fighter jets bombed last week, the interior minister said on Tuesday, seeking to quell rising doubts about the success of the operation."Some people are asking how many were killed," Rajnath Singh said at an election rally. "You are seeking answers from us! India's respected and authentic NTRO surveillance system has said that before Indian pilots dropped the bombs, 300 mobile phones were active there. There's no need to tell you how many were killed."Singh was referring to the National Technical Research Organisation that is under direct control of the prime minister's office.Indian opposition leaders are increasingly raising doubts about the government's official claims that a "very large number" of members of an Islamist militant group were killed in the strike by Indian warplanes early on Feb. 26. The government has rejected the demand for proof.Pakistan has said the Indian bombs hit a largely empty hillside near the northeastern town of Balakot without hurting anyone.A top Indian government official, speaking on condition of anonymity, said last week that at least 300 suspected militants were killed in the air strike, while the president of the ruling Bharatiya Janata Party (BJP), Amit Shah, put the figure at more than 250.