The protestors urged the world to try those responsible for the operation for war crimes.
Balad Chairman Jamal Zahalka, who attended the rally, said that "this is indeed the biggest demonstration we have seen over the past decade. The Arab public is united in its demand to stop the war immediately."
Zahalka added that Prime Minister Ehud Olmert, Defense Minister Ehud Barak and IDF Chief of Staff Gabi Ashkenazi must be tried by an international tribunal.
Hadash Chairman Mohammad Barakeh also arrived at the Sakhnin rally and said that "this demonstration is another important step we take pride in as part of the protest over the ongoing massacre against the Palestinian people in Gaza."
He added that "the demonstration is an answer to those betting on the Arab population's motivation to voice its steadfast opinion against the mentality of occupation and racism. We are here and will always be here until this mentality and all those who implement it are gone."
Knesset Member Wassil Taha (Balad) said during the rally, "This is one of the greatest demonstrations we have seen because it affects each and every family. People seek to express their pain by showing solidarity with the members of our nation.
"I call on the Israeli government – stop the killing, stop the crime. Stop the bombardments and hold real negotiations for just peace with everyone."
Sakhnin mayor: Long live the shahids
Ibrahim Zabidat, who led the rally, said during his speech, "The Israeli killing machine must stop. I call from here to the people in Gaza and say: Don't be afraid, don't give up, block them with your blood in order to build the state of Palestine, whose capital is Jerusalem. We, the people of Palestine, will continue to defend it through battle with our soul and blood and in peace."
He called on the Palestinian people in Israel to donate blood, money and food.
"This is the biggest procession in the history of the Palestinian people in Israel," declared Sakhnin Mayor Mazen Ghnaim. "The level of crowdedness in Gaza is one of the highest in the world, and yet the Israel Air Force jets are bombing and murdering innocent people.
"I call on Israel to end the war immediately and lift the siege. I send a greeting to Gaza's residents, who are facing the Israeli occupation machine. Long live Palestine, whose capital is Jerusalem, and long live the shahids (martyrs)."
Meanwhile, rightist activists from the Yisrael Beitinu went out to protest at four northern intersections. About 100 demonstrators headed to each junction and chanted "no citizenship rights without loyalty."
Yisrael Beiteinu Chairman Avigdor Liberman said in response to the mass protest in Sakhnin that "just as the Israeli government knows the operation in Gaza can't be stopped until Hamas is defeated, so must we act against those citizens of Israel not are not loyal to the State."
Yael Branovsky contributed to this report