President Pervez Musharraf appealed to Pakistanis yesterday to fight extremists in their midst, and officials said they were seeking the former aide of a radical cleric in Britain in connection with the July 7 bombings in London. Musharraf gave a nationally televised address as Britain’s ambassador, High Commissioner Mark Lyall Grant, said there have been no arrests in Pakistan related to the July 7 attacks, contradicting reports in recent days by Pakistani authorities that some suspects in the attacks were in detention. In his hourlong speech, taped before yesterday’s attempted bombings in London, Musharraf acknowledged Pakistan had a ”problem” with militants, amid international concern that Islamic schools here are promoting extremism. Full Story