WASHINGTON - US Defense Secretary James Mattis will visit Saudi Arabia, Egypt, Israel, Qatar and Djibouti starting on Tuesday, the Pentagon said in a statement on Friday. It said Mattis would 'reaffirm key US military alliances,' and 'discuss cooperative effort to counter destabilizing activities and defeat extremist terror organizations' during the April 18-23 tour. In Israel, he will hold talks with Prime Minister Benjamin Netanyahu, the statement said.