Foreign Minister Avigdor Liberman announced on Monday the breakup of the Knesset list his Yisrael Beytenu party shared with Prime Minister Benjamin Netanyahu’s ruling Likud party. The two parties ran together for the Knesset, but the law allows parties that run together to break up into separate Knesset factions once elected.

The move, announced at a press conference in the Knesset, could have a destabilizing effect on the ruling coalition, reducing the ruling party’s share of the Knesset’s 120 seats from 31 MKs to just 20 – just one more than coalition partner Yesh Atid.

Liberman told reporters that recently, longstanding differences between him and Netanyahu had become “essential, and no longer allow the existence of a shared framework.” He added that “the partnership didn’t work in the elections, and it didn’t work after the elections,” but that the two parties had maintained it so long as they did not have major differences on policy.

The move has been expected for some time. Over the past year, Liberman’s efforts to merge his party with Likud, supported by Likud chairman Netanyahu, have been rebuffed by the Likud rank and file in a series of votes in the Central Committee. The move was opposed by many senior Likud power brokers who did not want to see the formation of a new, organized power base within the party.

Liberman’s move to separate from the Likud is also tied to his party’s poor showing in recent polls. The party chairman believes that Yisrael Beytenu was hurt by the decision to run jointly with the Likud, shrinking its Knesset representation from 15 seats to 11.

The move is unlikely to destabilize the coalition in the short term. A top Yisrael Beytenu official, Deputy Interior Minister Faina Kirschenbaum, insisted the party did not seek to destabilize the government.

“We don’t think this is the time to split up the coalition and weaken it,” Kirschenbaum told Army Radio on Monday morning. “We want to strengthen the State of Israel.”

“We remain loyal members of the coalition,” Liberman said. “I don’t see any reason to break it up. We’re the last ones who want the breakup of the coalition.”

The current government, he said, “has no better alternative. As far as I understand it, new elections also won’t meaningfully change the division of power, of seats in the Knesset.”

The timing of Liberman’s announcement follows a public spat between the foreign minister and Netanyahu over the latter’s restrained response to the escalating rocket fire in Gaza.

“The reality in which we live with hundreds of rockets in the hands of a terror organization that can decide at any moment to use them is intolerable,” Liberman said Monday. “Suggestions to wait, listen, delay – it’s not clear to me what we’re waiting for. At the end of 2015 [Hamas] will have thousands of rockets [that can reach 80 kilometers]. We have to end this. We can’t live under this permanent threat, where 1.5 million people have to be ready to run to shelters at a moment’s notice.”

At the weekly cabinet meeting on Sunday, Netanyahu chastised ministers, including Economy Minister Naftali Bennett and Liberman, who spoke out publicly against the government’s policy on Gaza.

“Those who criticize publicly are being irresponsible,” Netanyahu told the ministers, adding that some were taking advantage of the delicate situation for their own political benefit. Once the cabinet makes a decision, the prime minister said, it is incumbent on ministers to support the decision in public.

Liberman reacted angrily, according to leaks from the closed-door meeting.

“You’re one to talk. You held press conferences before the cabinet even met,” Liberman shot back. “My criticism is consistent with what I’ve been saying for a long time; I’m not taking advantage of anything.”

Netanyahu noted in response that Liberman missed two recent cabinet meetings dealing with the Gaza situation. “Before you talk, come to cabinet meetings.”

Liberman, reportedly furious, responded that during one cabinet meeting he was on an official trip to Germany, and during another he was accompanying the speaker of the Armenian parliament and couldn’t get to the meeting in time.

“You said we would be strong in the face of Hamas, and you haven’t followed through on that statement,” he said. “At least you can’t accuse me of leaking from those meetings,” Liberman finished, according to the leaks.

The spat surprised some cabinet members. Finance Minister Yair Lapid urged minister not to talk “like internet talkbackers” in cabinet meetings.

The security cabinet has been deeply divided over Israel’s response to ongoing rocket fire in Gaza. Netanyahu, Defense Minister Moshe Ya’alon, Justice Minister Tzipi Livni and Lapid have urged restraint in responding to escalating rocket fire. Hamas is in dire straits with the closure of Gaza’s western border with Egypt and the collapse of the unity arrangement with the Palestinian Authority in the wake of the kidnapping-murders of three Jewish teens in the West Bank on June 12. A war is as likely to restore Hamas’s declining popularity among Palestinians as it is to harm the organization’s ability to continue launching rockets, sources close to the ministers have suggested.

Meanwhile, Liberman and Bennett have demanded a much stronger response to the Gaza fire, up to and including a ground incursion into the Strip. In part, the ministers have argued that Hamas has used the continued rocket fire to claim that it alone among Palestinian factions could defend Palestinian territory and honor against Israel. Continued restraint would be a strategic blunder, they believe, encouraging further attacks on southern towns.