Israeli Defense Minister, Moshe Yaalon, on Friday resigned, citing a lack of faith in Prime Minister Benjamin Netanyahu amid a reshuffle in the cabinet.
Netanyahu, from the right-wing Likud party, has been moving to replace Yaalon with hardliner Avigdor Lieberman, a former foreign minister.
He said that in a move meant to expand his coalition comprised already of several parties but which has only a one-seat majority in the legislature.
Lieberman, a nationalist populist, is the leader of the hawkish Israel Beiteinu party, which has six members in the Knesset.
However, he has relatively little military experience.
Most defense ministers in Israel have extensive backgrounds in the army, often serving as generals.
Yaalon said he would also resign from Knesset and take a break from politics.
He is due to be replaced in parliament by Yehuda Glick, a religious settler who lives on the occupied West Bank and has stirred up tensions over holy sites in Jerusalem.
Israel held elections in March 2015, returning Netanyahu to the premiership, a job he has held since 2009, and he was also prime minister for three years in the 1990s.
Report says peace talks between Israel and the Palestinians have since been frozen but additional hardliners in the government would make any chance of reviving them more remote.