He also denied that the Taliban is willing to negotiate with the Afghan government.
Mullah Omar accused Afghan President Hamid Karzai's government of being full of people who are "not interested in the future and prosperity of the country."
He also appealed for funding from Muslims around the world, which some take as a sign that NATO operations are hurting the militants.
Mullah Omar has not been seen in public since the U.S. invasion drove him from power.
The Associated Press contributed to this report.