JERUSALEM — The Israeli police recommended on Tuesday that Prime Minister Benjamin Netanyahu be charged with bribery, fraud and breach of trust, casting a pall over the future of a tenacious leader who has become almost synonymous with his country. The announcement instantly raised doubts about his ability to stay in office.

Concluding a yearlong graft investigation, the police recommended that Mr. Netanyahu face prosecution in two corruption cases: a gifts-for-favors affair known as Case 1000, and a second scandal, called Case 2000, in which Mr. Netanyahu is suspected of back-room dealings with Arnon Mozes, publisher of the popular newspaper Yediot Aharonot, to ensure more favorable coverage.

All told, the police accused Mr. Netanyahu of accepting nearly $300,000 in gifts over 10 years.

Mr. Netanyahu, addressing the nation live on television shortly before the police released their findings around 9 p.m., made clear that he would not step down. “I feel a deep obligation to continue to lead Israel in a way that will ensure our future,” he said, before embarking on a 12-minute defense of his conduct.

“You know I do everything with only one thing in mind — the good of the country,” he said. “Not for cigars from a friend, not for media coverage, not for anything. Only for the good of the state. Nothing has made me deviate, or will make me deviate, from this sacred mission.”