Israel's defense minister resigned on Friday, saying the nation was being taken over by "extremist and dangerous elements" after Prime Minister Benjamin Netanyahu moved to replace him with a far-right politician in an effort to strengthen his coalition. Political sources say Netanyahu has offered long-time rival Avigdor Lieberman the defense portfolio, a post crucial for a country on a perennial war footing. The Defence Ministry also runs civil affairs in the occupied West Bank, where Palestinians struggling for statehood live in friction with Jewish settlers. "To my great regret, I have recently found myself in difficult disputes over matters of principle and professionalism with the prime minister, a number of cabinet members and some lawmakers," outgoing Defence Minister Moshe Yaalon said, reading, grim-faced, from a statement at his Tel Aviv office.