TUNIS - Several thousand Islamists took to the streets of Tunis on Friday to defend the Islamist Ennahda government against calls for it to resign in favor of a unity government after the assassination of a secular opposition figure.A Reuters correspondent saw demonstrators chanting "The people want Ennahda again!" and "No to a coup against democracy!".Opposition politician Mohamed Brahmi was shot dead on Thursday in the second such assassination this year, setting off violent protests against the Islamist-led government in the capital and elsewhere.