* 300 Palestinians hurt in Jerusalem clashes

At least 20 people were killed, including nine children, and 65 others wounded in Israeli air strikes on the Gaza Strip after Palestinian militants fired rockets towards Israel, Hamas said.

Israel has said it was striking Hamas targets in retaliation for the dozens of rockets fired on Monday from the enclave towards Israel, but has not confirmed its strikes had caused fatalities.

The health ministry in Hamas-run Gaza said the updated death toll included a 10-year-old girl, while Hamas has confirmed that one of its commanders was killed in a strike.

More than 100 rockets were fired from Gaza towards Israel by multiple Palestinian armed groups, Hamas Islamists who control the blockaded enclave said.

Nine Palestinians were martyred , including three children, in an Israeli raid on Beit Hanoun in the north of Gaza, QNA said.

As Israel celebrated "Jerusalem Day" earlier on Monday, marking its capture of eastern sections of the holy city in the 1967 Arab-Israeli war, violence erupted at the Al Aqsa mosque, Islam's third most sacred site.

The Palestinian Red Crescent Society said more than 300 Palestinians were injured in clashes with police who fired rubber bullets, stun grenades and tear gas in the compound, which is also revered by Jews as the site of biblical temples.

The skirmishes, in which police said 21 officers were also hurt, at Al Aqsa had died down by the 6 pm deadline Hamas had set.

Reactions poured in from around the world after violence sparked by days of unrest at Jerusalem's Al-Aqsa mosque compound.

Turkish President Recep Tayyip Erdogan vowed to mobilise the world to stop Israeli "terror", in phone calls on Monday to Palestinian leaders.

In the calls to Palestinian president Mahmud Abbas and Hamas leader Ismail Haniyeh, Erdogan denounced Israel's actions and extended support.

US State Department spokesman Ned Price condemned the rocket attacks by Hamas as an "unacceptable escalation" and renewed calls for calm in Jerusalem.

Britain's Foreign Secretary Dominic Raab condemned the rocket attacks, saying "the ongoing violence in Jerusalem and Gaza must stop".

"We need an immediate de-escalation on all sides, and an end to targeting of civilian populations," he tweeted.

Iranian Foreign Minister Javad Zarif took to Twitter to blame Israel for stealing "people's land & homes" and creating "an apartheid regime".

He also accused Israel of refusing to vaccinate citizens "under illegal occupation" and accused Israeli police of shooting "innocent worshippers" inside the Al-Aqsa mosque.

Egypt's foreign ministry said in a statement it "firmly" condemned "the new incursion of Israeli forces into the al-Aqsa mosque".

Egypt's assistant minister of foreign affairs, Nazih Al-Najari met Monday with the Israeli ambassador in Cairo, Amira Oron, to say Egypt rejected and denounced Israel's action.

The UN Security Council held an urgent meeting on Monday over the violence, but issued no immediate statement.

Negotiations were continuing among the 15 nations on the Security Council on a text that could be watered down from an initial draft proposed by Norway.

But diplomats said the United States believed public comments would be counterproductive.

EU foreign policy chief Josep Borrell said the bloc was "deeply concerned over the recent clashes".

It was "important that everything possible will be done to avoid fuelling tensions", he added.

He described the evictions of Palestinians as a "matter of serious concern" and said "such actions are illegal under international humanitarian law".

He welcomed the decision to stop Jewish worshippers from accessing the esplanade as "a positive one that can calm the situation".