Israeli-Arab protesters have clashed with police as Jewish Israeli right-wingers marched in the majority-Arab town of Umm al-Fahm.
Thirteen arrests were made as police used tear gas and water cannons to disperse stone-throwing protesters.
Israeli-Arab residents of the town view the march as highly provocative and had vowed to stop it.
The High Court gave permission for the march, but police had postponed it several times, fearing violence.
About 2,500 police in riot gear flanked about 100 far-right activists as they marched on the outskirts of the town, waving Israeli flags.
The BBC's Katya Adler: "This is an extremely violent demonstration"
The march was over within an hour, but clashes broke out as dozens of young, male Israeli-Arab counter-demonstrators, some with their faces covered with Palestinian scarves, began pelting the police with rocks.
The BBC's Katya Adler at the scene described crouching behind a car with stones raining all around her.
She says that most of the crowd were angry but not violent, and older residents expressed disapproval as the rioting escalated.
A police spokesman said 15 police officers were injured, including Israel's deputy police commissioner.
'Raising Israeli flag'
The Israeli right-wingers said they wanted to exercise their right to march and raise the Israeli flag in any street in Israel.
One of the leaders of the march was Baruch Marzel, who led the anti-Arab Kach party that was banned in Israel in 1994.
"All we are doing is waving the Israeli flag. All we are demanding is loyalty to the state," another march leader, Michael Ben-Ari Ben-Ari, a member of the Israeli parliament, told the Israeli news website Ynet.
About 1.2m, a fifth of Israel's population, are Israeli-Arabs
They are citizens of israel, but face widely documented discrimination
Outgoing PM Ehud Olmert said there is "no doubt" Israeli-Arabs have faced discrimination for "many years"
Israeli-Arabs own 3.5% of Israel's land, get 3-5% of government spending and have higher poverty levels than Jewish Israelis*
There are 13 Israeli-Arabs in the 120-seat Knesset, 10 representing [primarly] Arab parties
"There is in Umm al-Fahm a gang of hooligans, who think they can win using violence. The State of Israel is the Jewish people's state. We are here to voice our truth and not to create provocations," he said.
Israeli-Arab residents of Umm al-Fahm consider the marchers racist, and had called a general strike and said they would use peaceful methods to prevent the activists from entering the town.
"Racism is not freedom of expression, it's a criminal act and the law should punish it," Israeli Arab MK Jamal Zahalka told the AFP news agency.
Jewish Israeli leaders from nearby towns also condemned the march as provocative, and some Jewish left-wingers were at the counter-demonstration.
The march took place on the outskirts of the town, after the High Court ruled the activists could enter its municipal boundaries but not residential areas.
The town is considered a stronghold of Israeli-Arab sentiment, and is also where 13 Israeli-Arab protesters were killed during riots as the last Palestinian uprising, or intifada, broke out in 2000.
Our correspondent says the anger on the streets of Umm al-Fahm is symptomatic of a growing sense of alienation among Israeli Arabs.
Leaders of the right-wing Israeli marchers say they are demanding Israeli-Arab loyalty to the state
She says many Israeli Arabs see the march as part of a growing trend within Israeli society of increased suspicion and intolerance towards them.
The march was planned about a year ago, but comes in the wake of a strong showing for the far right politician, Avigdor Lieberman, in Israel's recent elections.
Mr Lieberman advocates transferring majority-Arab areas in Israel to the control of the Palestinian Authority, and wants to bring in a citizenship law demanding that all Israeli citizens, including Israeli-Arabs, swear allegiance to Israel as a Jewish state.
He and other right-wingers accused Israeli-Arab leaders who were strongly critical of Israel during its recent operation in Gaza, of supporting Hamas.
Mr Lieberman's party is a key member of the right-leaning coalition that Prime Minister-designate Binyamin Netanyahu is putting together.
Israeli-Arabs make up about a fifth of Israel's population, and are descended from families who remained in Israel after the war that followed the state's creation in 1948.
They are full Israeli citizens, but face widely documented discrimination.
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