Gaza Strip – Thousands of Palestinians have taken to the streets across the Gaza Strip, denouncing the killing of six Palestinians by Israeli forces in the occupied West Bank city of Nablus early on Tuesday.

The demonstrations were held across the besieged Palestinian enclave, including the governorates of Rafah, Khan Yunis and Gaza City on Tuesday. Government and commercial offices were closed to observe a general strike called by Palestinian factions to mourn the dead, among whom were two unarmed barbers.

It coincided with massive protests in the occupied West Bank and East Jerusalem in the wake of the killings. Thousands of people attended the funerals of those killed on Tuesday in Nablus.

Protesters in Gaza’s public squares chanted slogans denouncing the “crime of the occupation”, and called on the Palestinian resistance to respond.

Ismail Radwan, a senior Hamas leader, told Al Jazeera: “The Israeli occupation, through its assassination of the martyrs of Nablus, has crossed all red lines.”

“The Israeli occupation will bear full responsibility for its crimes against our people, our sanctuaries, and the martyrs of our people, and the blood of the heroes of Nablus will not be wasted and will be fuel against the occupation,” he said.

Radwan condemned the international silence on “the crimes of the Israeli occupation” against the Palestinian people.

Tensions have been running high in the occupied West Bank for the past few months, with near-daily Israeli raids. Israeli forces have killed 184 Palestinians since the start of the year, including 51 in Gaza, according to the Palestinian health ministry. At least three Israeli soldiers have been killed in the past month in attacks carried out by Palestinians.

Khader Habib, a senior leader of the Islamic Jihad movement, also condemned the latest killings in Nablus, where resistance groups have emerged against Israeli occupation.

“National and Islamic factions are in a permanent meeting to follow up on the events in Nablus and the West Bank, and we’ll take the necessary steps to support our people in the West Bank,” he told Al Jazeera.

Palestinian youth set tires on fire on Tuesday afternoon near the separation barrier built by Israel along the line between it and Gaza. Black clouds covered the sky, as Palestinian flags were raised in solidarity with the people of Nablus.

Some people threw stones at the separation barrier, as Israeli soldiers remained stationed behind military vehicles.

Gaza, home to two million people, has been dubbed an open-air prison as it has been under an air, sea and land blockade imposed by Israel since 2007.

Ibrahim Abu Ahmed, 30, said he joined the protests at the fence to express his rejection of what is happening in Nablus. “We are one people and we will not allow the Israeli occupation to isolate Nablus from the rest of Palestinian land.”

“We call upon our brothers in the Lions’ Den and tell them we are with you, and we demand all our brothers in the West Bank to rally around the resistance, and we tell the occupation that Nablus is not alone,” he said referring to Lions’ Den group whose members have carried out attacks against Israeli forces.

Ibrahim called on brotherly countries and human rights organisations to intervene in light of what is happening in the occupied West Bank.

“Enough with the policy of silence pursued by countries towards Israeli occupation,” he said.