JERUSALEM — Prime Minister Benjamin Netanyahu is fighting for voter support with dire predictions of an Arab-supported coalition as his Likud begins to trail the Labor-led Zionist Union in polls ahead of March 17 elections.

“There is a good chance that Bougie Herzog and Tzipi Livni will be the next prime ministers of Israel,” Netanyahu said in a Channel Two interview Thursday, referring to his rivals by their nicknames. “There is such a danger, if we don’t close the gap in the coming days.”

Livni and Isaac “Bougie” Herzog, co-leaders of the Zionist Union ticket, have agreed to take turns as prime minister if they form the next government. A poll in the daily Haaretz on Thursday showed Zionist Union, which favors renewed peacemaking with the Palestinians, winning 24 of parliament’s 120 seats to Likud’s 21. Two polls published Tuesday showed similar outcomes.

In the YouTube video posted on Wednesday, Netanyahu urged potential supporters to vote for Likud instead of other parties that share its opposition to territorial concessions to the Palestinians, warning that otherwise Herzog and Livni, “with Arab support,” would form the next government. A coalition of Arab parties is running in third place, according to some recent polls.

The prime minister, who called snap elections in December after months of acrimonious relations with coalition partners, is finding himself in a tight race to win a fourth tenure. Because neither Likud and Zionist Union will capture a parliamentary majority, either one would have to form a coalition to govern. While Likud is trailing in number of seats, polls indicate it would have an easier time forming a coalition with parties that take a similarly hard line against territorial concessions to the Palestinians.