More than 150 people were wounded Friday in clashes between Palestinian demonstrators and Israeli police in Jerusalem's Al-Aqsa mosque compound, the first face-off at the flashpoint holy site since the start of Ramadan.
Israeli police said dozens of masked men marched into Al-Aqsa setting off fireworks before crowds hurled stones towards the Western Wall -- considered the holiest site where Jews can pray.
Witnesses said Palestinians threw stones at Israeli forces, who fired rubber-coated bullets and stun grenades.
The Palestinian Red Crescent said 153 people were hospitalised and "dozens" of others were treated at the scene. Israeli police said at least three officers were hurt.
Around 400 people were arrested, the Palestinian Prisoner's Club said.
The clashes come after three weeks of deadly violence in Israel and the occupied West Bank, and as the Jewish festival of Passover and Christian Easter overlap with the Muslim holy month of Ramadan.
Al-Aqsa is Islam's third-holiest site. Jews refer to it as the Temple Mount, referencing two temples said to have stood there in antiquity.
Last year during the Muslim fasting month, clashes that flared in Jerusalem, including between Israeli forces and Palestinians visiting Al-Aqsa, led to 11 days of devastating conflict between Israel and Hamas, the Islamist group that rules the Palestinian enclave of Gaza.
Israeli Foreign Minister Yair Lapid said Friday's "riots" were "unacceptable".
"The convergence of Passover, Ramadan and Easter is symbolic of what we have in common. We must not let anyone turn these holy days into a platform for hate, incitement and violence," he said.
UN Middle East peace envoy Tor Wennesland urged "the authorities on both sides to immediately de-escalate the situation and prevent any further provocations by radical actors".
The US, European Union and the Arab League have also voiced their concern.
Washington on Friday said it was "deeply concerned" by the events in Jerusalem.
"We call on all sides to exercise restraint (and) avoid provocative actions and rhetoric," State Department spokesman Ned Price said in a statement.
Police said crowds had hurled rocks "in the direction of the Western Wall... and as the violence surged, police were forced to enter the grounds surrounding the mosque," adding officers did not enter the mosque.
But Al-Aqsa mosque director Omar al-Kiswani told AFP that an "assault was made inside the Al-Aqsa mosque".
"More than 80 young people inside the holy mosque were displaced," he said, adding: "Al-Aqsa mosque is a red line".
Before Ramadan, Israel and Jordan stepped up talks in an effort to avoid a repeat of last year's violence.
Jordan serves as custodian of the mosque compound, while Israel controls access.
Hamas leader Ismail Haniyeh said there was "no place for the invaders and occupiers in our holy Jerusalem".
Analysts say Hamas wants to keep the conflict alive in the West Bank and in Jerusalem but avoid escalation in the Gaza Strip after last year's war, and with thousands of Gazans' Israeli work permits at risk.
"Hamas does not want a new confrontation," said Mukhaimer Abu Saada, professor of political science at Gaza's Al-Azhar University.
An Israeli security source said the Islamic Jihad militant group -- which controls neither the West Bank nor Gaza -- would be more inclined towards an escalation with Israel.
The group warned "the confrontation will be closer and harder" for Israeli forces if "they do not stop the aggression against our people".
Along with Hamas, Islamic Jihad mobilised thousands of people in Gaza on Friday in solidarity with Palestinians at Al-Aqsa, AFP correspondents reported.
Israel has poured additional forces into the West Bank and is reinforcing its wall and fence barrier after four deadly attacks in the Jewish state in the past three weeks.
A total of 14 people have been killed in the attacks since March 22, including a shooting spree in Bnei Brak, an Orthodox Jewish city in greater Tel Aviv.
Twenty-two Palestinians have been killed over the same period, including assailants who targeted Israelis, according to an AFP tally.
On Thursday, Israel announced it would block crossings from the West Bank and Gaza into Israel from Friday afternoon through Saturday, the first two nights of Passover week, and potentially keep the crossings closed for the rest of the holiday.
Prime Minister Naftali Bennett, who lost his parliamentary majority last week, has given Israeli forces a free hand to "defeat terror" in the West Bank, which Israel has occupied since the Six-Day War of 1967.
Some of the attacks in Israel were carried out by Arab citizens of Israel linked to or inspired by the Islamic State group, others by Palestinians, cheered by Hamas and Islamic Jihad.
Three Palestinians died Thursday as Israeli forces launched fresh raids into the West Bank district of Jenin, a week after a deadly gun attack against a Tel Aviv nightlife district. A fourth died of his wounds on Friday.