TOKYO, Sept 2 (Reuters) - Japan's Chief Cabinet Secretary Yoshihide Suga said he would hold a briefing on the ruling party's leadership election later on Wednesday, all but confirming plans to announce his candidacy in a race he is widely expected to win.

Suga, a longtime ally of Prime Minister Shinzo Abe, has privately indicated his intention to stand for leader of the ruling Liberal Democratic Party (LDP), a source has told Reuters. The party's leader will almost certainly be the next prime minister given the LDP's majority in the lower house of parliament. (Reporting by Kaori Kaneko; Writing by David Dolan Editing by Shri Navaratnam)