A pro-Taliban gunman said Usmani was a prayer leader in a mosque in north Waziristan and an opponent of the fighters.
"He recorded several cassettes in which he criticised us and the Taliban," an armed fighter said by telephone. He declined to comment when asked who had killed Usmani.
"He recorded several cassettes in which he criticised us and the Taliban"
Gunmen in the north and south Waziristan have killed dozens of people they accused of being Pakistani government supporters or US spies.
Many Taliban and al-Qaeda fighters fled to Pakistan's semi-autonomous tribal lands from Afghanistan after US-led forces toppled the Taliban in 2001.
Pakistani forces tried to clear out foreign gunmen and subdue their Pakistani allies after 2001 and hundreds of people were killed.
But the government later signed peace deals aimed at ending the fighting and stopping raids into Afghanistan.
Critics say the deals have given the fighters free rein and led to the "Talibanisation" of a region that has become a haven for al-Qaeda and the Taliban.
Pervez Musharraf, the Pakistani president, and his government - a major ally in the US-led war on terrorism - defends the deals and dismisses concern about Talibanisation.