By New York Times

Prime Minister Alexis Tsipras called on Sunday for a vote of confidence in the Greek government, hours after a junior coalition partner announced that he would quit in protest of a deal to end a dispute with Macedonia over its name.

The move threw the country into new political turmoil, fueling speculation about possible snap elections, although Mr. Tsipras said his government aimed to complete its term into October.

The coalition partner, Defense Minister Panos Kammenos, who is also the leader of the right-wing Independent Greeks party, announced his resignation following talks at the prime minister’s residence.

“The Macedonia name issue does not allow me not to sacrifice my post,” the minister told reporters afterward. “ANEL is leaving the government,” he said, using the Greek acronym for his party.

His decision came days after Macedonian lawmakers agreed to officially change the country’s name to the Republic of North Macedonia, ending a long dispute with Greece and opening the door for the small Balkan nation’s membership in NATO and the European Union.

Greece has long argued that Macedonians were a Hellenistic people and therefore the name could not be claimed by the Slavic people living in the country today. Since NATO requires unanimity to accept a new member, Greece has effectively kept Macedonia out of the security alliance.

Shortly after Mr. Kammenos’s decision, the leftist prime minister thanked the defense minister for his “irreplaceable, important contribution” to the government.

“Our ideological differences with Kammenos were well known,” he added. “Despite this we cooperated honestly and we achieved a lot of significant things, most importantly extracting the country from the upheaval of the memorandums,” he said, referring to Greece’s emergence from its third international bailout last summer.

Declaring that his goals now were to continue a range of reforms and “upgrade the country’s role on the international stage,” Mr. Tsipras said he would seek a confidence vote “directly” so that his government could complete its term.

“Each must now face their historic responsibilities,” he said.

The vote was expected to be held this week, after two days of debate from Tuesday morning, according to a recommendation by the Parliament speaker, Nikos Voutsis.

Mr. Tsipras appointed Adm. Evaggelos Apostolakis, the director of the Hellenic National Defense General Staff, as defense minister.

After months of friction over the Macedonia name change, Mr. Tsipras suggested in a television interview last week that he would seek a vote of confidence rather than snap elections if Mr. Kammenos withdrew his support. He conceded, however, that although the Greek Constitution would allow him to continue to govern with a minority government, “politically” there would be a problem.

The governing coalition has 153 seats in the 300-seat Parliament — 145 held by the leftist Syriza and the other seven by ANEL. Growing upheaval within the fragile coalition in recent months has fanned speculation that elections will be brought forward, most likely to May, when the European Parliament and local authority elections are scheduled.

After Mr. Tsipras’s announcement, Mr. Kammenos said at a news conference on Sunday that he would not support a confidence vote in Parliament, and that any party members who insisted on maintaining their cabinet position would be expelled from ANEL.

He also called for a referendum in May on the Macedonia name deal, which was signed by Athens and Skopje last June and ratified on Friday by Macedonia’s Parliament. The vote by Macedonian lawmakers was one step toward ending a long-running dispute with Greece, where a northern region also bears the Macedonia name.

“It is not a deal; it is a capitulation,” Mr. Kammenos said of the agreement, echoing a sentiment echoed by many Greeks who believe that the pact implies claims to Greek territory, since Greece has a northern region named Macedonia.

Thousands of Greeks took to the streets over the summer to protest the agreement over the name change, adding further pressure on Mr. Kammenos to adhere to his much-repeated line that he was ideologically opposed to the Macedonia deal.

Citizens’ groups opposing that deal have called for a protest rally in Athens for Jan. 20. The main conservative opposition party New Democracy, which is far ahead of Syriza in opinion polls, also vehemently opposes the deal.

The secretary general of NATO, Jens Stoltenberg, however, called it a historic moment and a victory for the Macedonian people. “NATO strongly supports the full implementation of the agreement, which is an important contribution to a stable and prosperous region,” he said.

The name change must now be approved by the Greek Parliament and is expected to go to a vote this month, Mr. Tsipras said in his interview last week. Government officials have repeatedly expressed confidence that the deal will pass into law with the support of lawmakers from smaller opposition parties.

Greece’s next parliamentary elections are scheduled for October 2019, and it was not immediately clear on Sunday whether two other Independent Greeks ministers, the tourism minister, Elena Kountoura, and the deputy minister for rural development, Vasilis Kokkalis, would quit the government as Mr. Kammenos did.

On Sunday, Mr. Tsipras said that he had accepted Mr. Kammenos’s resignation and would also accept any other resignations, a statement widely understood as leaving the door open for ANEL ministers to remain in the leftist-led coalition.

Of the six ANEL ministers, only one, deputy foreign minister Terence Quick, reacted immediately, saying he would support the government in the vote. At least two ANEL lawmakers have suggested they will back the name deal, breaking ranks with Mr. Kammenos.

On Saturday, Greece’s Supreme Court prosecutor, Xeni Dimitriou, ordered an investigation into news reports that lawmakers had received threats to vote against the agreement.

The deal first prompted upheaval within Mr. Tsipras’s cabinet last October, when Foreign Minister Nikos Kotzias, who signed the pact with his Macedonian counterpart, quit amid growing tensions with Mr. Kammenos.

Unlikely political bedfellows Syriza and ANEL came to power in January 2015 on a pledge to crack down on corruption and to roll back the austerity measures previous governments put in place secure rescue loans for the debt-racked country.

The prime minister assumed the duties of the foreign minister in October in order to lead the negotiations on the Macedonia deal, drawing praise from the European Union for helping to steer the agreement.

In a two-day visit to Greece last week, Chancellor Angela Merkel of Germany expressed gratitude to Mr. Tsipras for leading efforts to resolve the dispute between Athens and Skopje, which dates to 1991, when Macedonia declared independence during the breakup of the former Republic of Yugoslavia.

Greece has a long track record of votes of confidence in the governments that led the country during the years it was plagued by a crippling debt crisis.

The vote this week will mark the seventh time the Greek Parliament has hosted such a vote in less than eight years. It will be the third vote of confidence in a government led by Mr. Tsipras; his coalition survived the last one, in October 2015.