JERUSALEM - Israeli diplomats launched an unprecedented strike on Sunday, forcing the complete closure of embassies around the world as they escalated a dispute over pay, officials said. The industrial action has already threatened to postpone a visit by Pope Francis to Israel planned for May - one of 25 trips by foreign officials affected by a work slowdown the diplomats began on March 5 when wage talks broke down.

By escalating the action to a full strike - the first by the diplomatic corps since the country’s establishment in 1948 - the diplomats will close all of Israel’s 102 missions abroad, paralysing most diplomatic work with other countries and the United Nations.

“We are completely shutting down the (foreign ministry) office and missions abroad. This is the first time ever,” ministry spokesman Yigal Palmor said.

Another ministry official told Reuters: “As of now, the foreign ministry doesn’t exist. It’s not possible even to submit complaints”. Foreign Minister Avigdor Lieberman Called the strike “irresponsible” and “a wretched decision and a display of a loss of control on union’s part.”

“We shall do whatever possible to minimise the damage to the country and its citizens,” Lieberman said. Diplomats said the strike - involving some 1,200 foreign service employees - was open-ended and had been called after the Treasury had failed to present any acceptable proposals.

They are demanding an increase in monthly salaries, which they put at 6,000-9,000 shekels ($1,700-$2,600), and want compensation for spouses forced to quit jobs due to foreign postings. They say about a third of their number has quit in the past 15 years due to poor wages.

Yacov Livne, spokesman for the diplomats’ union, said: “the Treasury is determined to destroy the foreign ministry and Israeli diplomacy.”

Meanwhile, tens of thousands of Palestinians rallied in Gaza on Sunday to show support for their Islamist Hamas government, which has long been at loggerheads with Israel but is now shunned by Egypt as well.

The military-backed government that toppled the Muslim Brotherhood, Hamas’s ideological kin, in Cairo last year has blacklisted the Brotherhood and Hamas as terrorist groups and clamped down on people, goods and arms crossing the Sinai-Gaza border. Hamas tried in vain to mollify Egypt by insisting that its hostility was directed exclusively at Israel, but is now turning up the rhetoric.

“The punishment of the people of Gaza must end,” Ismail Haniyeh, head of the Hamas government, told the rally in a speech interspersed with chants of “Jihad is not Terrorism” over the loudspeakers.

“Why punish Gaza? Was it because it achieved victory against the Occupier? Why punish Gaza? Was it because it took up the rifle against Israel?” Haniyeh said.

“We are living through a difficult stage and harsh challenges, but we are not terrified and we are not defeated. We have become familiar with difficulties and this stage is not the most difficult.”

Hamas has repeatedly fought Israel, which withdrew from the Gaza Strip in 2005. The Islamists won a Palestinian legislative election the next year and, after a uneasy power-share with the U.S.-backed rival faction Fatah, seized control of Gaza in 2007.

Sunday’s rally was intended to commemorate three top Hamas leaders, including the group’s founder, Sheikh Ahmed Yassin, who was assassinated by Israel a decade ago.

The tone of defiance appeared aimed in part at undermining Palestinian President Mahmoud Abbas of Fatah, who holds sway in the Israeli-occupied West Bank and is holding peace talks with Israel under Washington’s auspices.

“We call upon the Palestinian negotiator to quit this pointless track and not to extend negotiation,” said Haniyeh.

Though Hamas has largely held fire since its last war with Israel, in November 2012, the Israelis have been uncovering tunnels dug from Gaza to allow cross-border attacks in the next confrontation. Haniyeh said the tunnels showed his faction’s dedication to fighting Israel until its eventual destruction.

“From below ground and above ground, you, the Occupiers, will be dismissed. You have no place in the land of Palestine.”

Haniyeh described Egypt as “brother, friend and neighbour”, but another Hamas official based in the West Bank, Hassan Youssef, had harsher words.

“We say to the authors of the coup in Egypt, the criminals who support the Occupation (Israel), that the blockade will not work,” he said in a televised speech.

Cairo’s cold shoulder has exacerbated Hamas’s isolation since it quit its headquarters in Damascus in protest at Syrian President Bashar al-Assad’s crackdown on opposition groups, a move that led Iran to cut off funding.

Palestinian officials said Hamas was now in fence-mending talks with Tehran, though their outcome remained unclear.