PESHAWAR (Reuters/AFP) - The military said on Thursday that 23 more militants had been killed and another five captured in the previous 24 hours during operations in the northeast. But no Taliban leaders have been among the approximately 1,600 militants the Army has reported killed in Swat. Independent casualty estimates are not available. Military spokesman Major-General Athar Abbas said media reports on Thursday that Swat Taliban leader Fazlullah had been killed were not confirmed. The failure to kill or capture leaders of the Taliban in Swat has led to fears that the militants could make a comeback if and when the army withdraws from the valley. As the army nears the end of its push in Swat, it has begun attacking Taliban chief Baitullah Mehsud in his South Waziristan stronghold in mountains on the Afghan border. The army says Mehsud is behind 90 percent of militant attacks in Pakistan. The military said that troops had killed more than 50 militants while ground and air forces battled against insurgents in parts of the northwest. At least 28 militants of Lashkar-e-Islam were killed in shelling by helicopter gunships, Major Fazal Khan, a spokesman for the paramilitary Frontier Corps unit, told AFP. He said the operation was conducted overnight in the Tirah Valley of Khyber, one of countrys seven semi-autonomous tribal areas and through which flows the bulk of supplies destined for US-led and NATO troops in Afghanistan. Lashkar-e-Islam said eight of its members died. Eight of our members were killed. We dont know about the rest, they might be civilians, Mistri Gul, a spokesman for the group, told AFP. In June 2008, Pakistan poured paramilitary troops into Khyber to counter militants threatening to take over Peshawar and to stop attacks on convoys supplying Western troops based in Afghanistan. Authorities accuse the radical Lashkar-e-Islam of kidnapping for ransom in Peshawar, running torture centres and private jails. The group is also accused of attacking convoys ferrying supplies to NATO and US troops in Afghanistan that travel through the historic Khyber Pass. In Swat, the military said security forces had killed 23 militants, including 17 around Shah Dheri in clashes, during the last 24 hours.