Shops, factories, schools and offices in the occupied will close as local unions called on global supporters to take to the streets in protest of Israeli air strikes in the Gaza Strip and Israeli settler attacks on Palestinians in the occupied West Bank.
Fatah issued a statement on Monday backing the strike action, adding that "the Palestinian people are fighting a fateful battle that requires unprecedented unity among all internal factions, so we can unite against the enemy".
Student unions at Palestinian universities in the West Bank urged all Palestinian sectors to take part in the strike.
Fatah's youth movement said in a statement that it will join the 18 May industrial action, adding that students will join protests against Israeli occupation.
Shops and commercial stores in Ramallah have been closed since Saturday in a show of solidarity with the families of the 21 people killed by Israeli forces last week.
The High Follow-Up Committee for Arab Citizens of Israel endorsed the strike action and called on Palestinian citizens of Israel to take part.
Palestinian citizens of Israel number approximately 1.6 million people - around one-fifth of the population.
Palestinian groups also called on Palestinians abroad and supporters to hold demonstrations outside Israeli embassies.
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Since Monday, at least 219 Palestinians have been killed by Israeli violence and 5,588 others injured, according to figures issued by Palestinian health ministries.
At least 200 Palestinians have been killed by Israeli airstrikes on Gaza since last Monday, including 59 children and 35 women, and more than 1,300 injured.
In the occupied West Bank, 21 Palestinians have been killed by Israeli forces and 4,363 have been wounded, after demonstrations broke out last week, according to the Palestinian health ministry.
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