Large Palestinian protests against Israel’s assault on the Gaza Strip spread across the West Bank on Friday, as U.S.-led talks to secure a lasting truce sputtered while Gaza residents awaited a possible lull in fighting.

In Cairo, Secretary of State John F. Kerry said Friday that his efforts to reach a week-long cease-fire in the Gaza Strip fell short. But as condemnation against the Israeli rejection of Kerry’s terms rose, Prime Minister Benjamin Netanyahu agreed to a 12-hour “humanitarian pause” in the fighting, to begin at 8 a.m. Saturday. Hamas, the militant group that controls Gaza, announced early Saturday that it would also abide by the pause.

In the occupied West Bank, at least five demonstrators were killed in clashes with Israeli security forces Friday, according to local news media reports. Two Palestinians were shot dead in a northern village where protesters rioted, and three Palestinians were killed in a southern village during clashes with Israeli soldiers, the reports said.

Kerry had hoped to announce a temporary truce between Israel and Hamas on Friday, envisaging a week-long cease-fire that would begin as the Muslim holiday of Eid al-Fitr begins over the weekend and allow time for deeper negotiations that might address Israeli security concerns and loosen Israeli and Egyptian prohibitions on Gazans’ travel and trade.

But Israeli cabinet ministers rejected Kerry’s proposal for a cease-fire, according to Israeli media accounts. Michael Oren, a former Israeli ambassador to the United States, said Israel does not want Hamas, the militant organization that runs Gaza, to use a week-long cease-fire to redeploy its fighters and rockets. Israel also wants to retain its ability to search for and destroy infiltration tunnels used by Palestinian militants to sneak into Israel from the Gaza Strip.

Graphic: See how many rockets Hamas has launched into Israel and how many targets Israel has struck in Gaza

Netanyahu was under no domestic pressure to end the fighting in Gaza, said Oren, who called the mood in Israel “intensely resilient.”

“We have had twice as many losses as we had in the last two operations” against Hamas in Gaza, he said. “There is a strong sense that we have to go on and pressure Hamas to reach a fundamental change, that Hamas needs to demilitarize.”

Kerry, speaking alongside U.N. Secretary General Ban Ki-moon and Arab diplomats, said he will leave the region after five days and head next to Paris to try to enlist European help. Kerry claimed progress, but acknowledged that Israel “has some questions.” With evident irritation, he said the Israeli cabinet vote was engineered to make “mischief.”

As Kerry made a last-ditch round of telephone calls, Israeli airstrikes on Friday hit 30 houses in Gaza, including the home of Salah Hassanein, a leader of the military wing of Islamic Jihad, a militant faction. Hassanein, 45, and two of his sons, ages 12 and 15, were killed, Islamic Jihad said. Local reporters in Gaza said he was a war propagandist and was not well known.

Rockets fired from the Gaza Strip continued to reach into Israel, including Tel Aviv, although at a slower pace than the previous days.

Following Friday prayers, Palestinian protesters in the West Bank declared a “day of rage” against Israel’s assault on Gaza, and demonstrations that began Thursday night spread rapidly across the occupied territory and East Jerusalem.

It was the last Friday of the Muslim fasting month of Ramadan, known as al-Quds Day, and Israeli police attempted to prevent violence by deploying additional police units and allowing only women and men over 50 to attend prayers in the al-Aqsa Mosque in Jerusalem’s Old City.

Amid renewed fighting between Israel and the Palestinian territories, The Post’s Ishaan Tharoor offers a background on the decades-old conflict and the current escalation. (Davin Coburn/The Washington Post)

Thousands gathered at the main mosque in the West Bank city of Qalandia to mourn the death of Muhammad al-Araj, 17, the lone Palestinian killed during the demonstrations Thursday night. Toward the end of the prayers, a preacher urged Muslims to rise up against Israel.

“I call upon the armies of the Arabs and the Muslims to stand up for the victims and to seek revenge for the actions of the Israelis, who are killing innocent children in cold blood,” he shouted into a microphone.

The Israeli media was consumed with questions about whether the events signaled the beginning of the third intifada, or uprising. “These demonstrations are not peaceful,” Kobi Michael, former head of the Palestinian desk at Israel’s Ministry of Strategic Affairs, said in an interview. “They are very violent demonstrations, very well organized and not at all spontaneous.”

Palestinians said the Israelis do not understand their outrage over the killing of civilians, including women and children, in Gaza.

Diana Buttu, a Palestinian analyst, said that Thursday night’s protest in Ramallah was an “amazing scene,” much bigger than any demonstration she has seen in the West Bank in recent years.

“People were united,” she said, people waved mostly Palestinian flags — not flags of the various rival political factions.

On Friday, the mourners carried Araj’s corpse, wrapped in a shroud with the colors of the Palestinian flag, down a narrow street toward the cemetery.

“Enough is enough,” the crowd chanted, as if talking to Israel. “You’ve reached your limit.”

On Thursday, a Gaza elementary school where hundreds of Palestinian evacuees had sought shelter under U.N. protection came under heavy fire. Sixteen people were killed, and more than 100 were injured. It was unclear whether Israel had fired on the school or whether mortars or rockets fired toward Israel by Hamas had fallen short.

The United Nations sent a team, including a weapons expert, to the school on Friday in an effort to determine who fired the deadly barrage.

“The mission had to be cut short and the team was forced to leave the area after gunfire around the school,” said Christopher Gunness, a spokesman for the U.N. Relief and Works Agency, which ran the facility.

The Palestinian death toll in Gaza topped 800 as the conflict reached its 18th day. On the Israeli side, at least 35 soldiers, two Israeli civilians and a Thai guest worker have been killed.

Israel announced Friday that one of its soldiers who was previously listed as missing in action, Sgt. Oron Shaul, was officially declared “killed in action whose burial site is unknown.” Earlier, Hamas had said it had “captured” Shaul and displayed his photo identification card, but they never produced photographs of a body or Shaul.

Israel also announced Friday that another soldier was killed by mortar fire launched from the vicinity of a U.N.-run Palestinian school.

Booth reported from Gaza City and Eglash from Jerusalem. Anne Gearan in Cairo contributed to this report.