TEHRAN, Iran (AP) _ President Mahmoud Ahmadinejad on Tuesday challenged the authority of the U.N. Security Council as Iran faces a deadline to halt its uranium enrichment and he called for a televised debate with President Bush on world issues. The Security Council has given Iran until Thursday to suspend enrichment, a process that can produce either fuel for a reactor or material for weapons. ``The U.S. and Britain are the source of many tensions,'' Ahmadinejad said at a news conference. ``At the Security Council, where they have to protect security, they enjoy the veto right. If anybody confronts them,...