* Violence during Ramadan lays bare Israeli-Palestinian tensions
* Police work to separate Israeli, Palestinian protesters
* Israelis march through Jerusalem chanting anti-Arab slogans
* U.S. Embassy in Jerusalem calls for calm (Adds statement from U.S. Embassy in Jerusalem, comment from Israeli far-right politician, bullet points)
By Stephen Farrell and Rami Ayyub
JERUSALEM, April 23 (Reuters) - After a night of violence in Jerusalem, Israeli police made over 50 arrests and Palestinian medics said 100 were injured during Ramadan clashes in the contested city at the core of the Israeli-Palestinian conflict.
From late Thursday night into early Friday, police in riot gear and on horseback fought to keep apart two groups of protesters - Palestinian youth hurling firecrackers and setting fire to garbage bins, and ultra-nationalist Israelis chanting anti-Arab slogans.
Police deployed armoured vehicles spraying foul-smelling skunk water towards the two groups - Palestinians gathered around Jerusalem's historic Damascus Gate and hundreds of right-wing Israelis several hundred metres away.
Clashes and other violent incidents between Palestinians and Israelis have occurred nightly since the start of the Muslim fasting month of Ramadan.
Palestinians say police have tried to prevent them from holding their usual Ramadan evening gatherings outside Damascus Gate, an historic landmark on the north side of the Old City and adjacent to several Palestinian neighbourhoods.
Meanwhile, a video on social media app TikTok purporting to show a Palestinian slapping an ultra-Orthodox Jewish man on Jerusalem's light rail train has drawn protests by Israelis and calls by far-right politicians for tougher police action.
The incidents have threatened to break a sustained period of relative quiet in the holy city. On Thursday night, hundreds of ultra-nationalist Israelis - many of them young and religious - marched through central Jerusalem towards the Damascus Gate, which police had barricaded as a precaution.
As they marched, many chanted "Death to Arabs" and some waved banners reading: "Death to terrorists".
One participant, David, 40, said he lived far from Jerusalem but "came here to support my own people", adding: "I'm Jewish and I'm a patriot and I'm proud of my country."
Police fired skunk water at the Israelis, pushing them away from their position at the Old City's New Gate - just 600 metres (yards) away from Palestinians gathered at Damascus Gate - and towards Jerusalem's central Jaffa Road.
U.S. SEEKS RETURN TO CALM
In a statement in English, Hebrew and Arabic, the U.S. Embassy said it was "deeply concerned" about the violence.
"We hope all responsible voices will promote an end to incitement, a return to calm, and respect for the safety and dignity of everyone in Jerusalem," it said.
The anti-Arab slogans appeared to draw a rebuke from far-right Israeli politician Itamar Ben-Gvir.
"I am against such chants," he told radio station 102 FM, while defending the Jewish demonstrators' right to protest.
He added: "There are many Arabs among us who are loyal. But I certainly think that those of them among us who lynch, who beat up, cause harm - they should be roughed up, they should be thrown out of here."
Asked what he meant by "roughed up", Ben-Gvir said it meant prosecuting them and also "if we manage to pass legislation, also throwing them out of the country."
As Palestinians heard reports of the Israeli crowd approaching, they gathered near Damascus Gate with ambulances racing up and down crowded backstreets with sirens blaring.
Police sealed off the area to prevent the Israeli and Palestinian crowds from potentially meeting. The Palestinians dragged garbage bins, some of them ablaze, into the roads on their side to disrupt police and block them from their side. Some discharged small fireworks towards police.
In all, police said they arrested over 50 people overnight, without distinguishing between Israelis and Palestinians. The Palestine Red Crescent said 100 Palestinians had been injured, with 21 taken to hospital but none of them serious.
The Palestinian clashes with Israeli police began with the start of Ramadan, on April 13. Palestinians say police have tried to prevent them from holding their usual Ramadan evening gatherings outside Damascus Gate.
"Palestinians love to relax in this area after evening prayers at Al-Aqsa Mosque, but the occupation (Israel) doesn't like it. It's a matter of sovereignty," said Jerusalem resident Mohammad Abu Al-Homus, pointing to metal barricades thrown up by police in the area in recent weeks.
Police say the measure is part of efforts to ensure Muslim worshippers can safely get to the main Islamic prayer site in the Old City, known as the Noble Sanctuary.
"Since Damascus Gate is the main way to reach and enter the Old City, police forces carry out field activities using various means to prevent friction, violence and confrontation, and to maintain order and security ... ," said a police spokesman.
Israel claims all of Jerusalem, including the eastern sector captured in the 1967 Middle East war, as its capital. Palestinians seek to make East Jerusalem, including its Muslim, Christian and Jewish holy sites, capital of a future state. (Additional reporting by Dan Williams Editing by William Maclean)
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