The ultra Orthodox community's protest is expected to climax at 7:30 pm, with tens of thousands of people arriving for a mass prayer on Bar Ilan Road.
"We will show zero tolerance against violent riots," a police official said Friday.
The ultra-Orthodox community and the Committee for the Sanctity of Shabbat announced that the planned prayer was backed by Rabbi Ovadia Yosef, leader of the haredi-Sephardic community, and by Rabbi Yosef Sholom Elyashiv, leader of the Lithuanian public.
Community sources added that they were very proud of the wide-scale support for the protest, which includes all haredi factions.
A source close to Rabbi Yosef told Ynet that "the rabbi is afraid that opening the parking lot will lead to further things of this king, like the opening of additional businesses and parking lots."
According to the sources, when the rabbi was asked whether he would join the protest prayer, he gave a positive answer but did not take any active measures like issuing a sermon on the matter.
A source close to Rabbi Elyashiv said that he had taken a similar approach. "The rabbi is not a supporter of demonstrations. He expressed his support through a verbal approval of the prayer rally, but did not sign and has not called on his public to take to the streets. The rabbi hopes that a compromise will be reached."
Seculars to protest tooTwo weeks ago, a police officer was hit and injured by a stone during violent clashes between haredi protestors and police forces following the opening of the Safra parking lot near the city hall. Five additional policemen were hurt by other objects hurled at them. The protestors threw dirty diapers and bottles and called the police "Nazis".
Following the violent protests, Jerusalem Mayor Nir Barkat announced that the disputed parking lot would be closed for two weeks of dialogue, in an attempt to reach a compromise.
On Thursday, the court approved the opening of an alternative location – the Karta parking lot – prompting the haredi community to renew their protest.
Hundreds of police officers are expected to deploy in the points of friction Friday evening, focusing on Bar Ilan Road. "We estimate that there will be no violent riots," a police official said, "but we are preparing for such a possibility.
"As long as the protest is legitimate and organized we will allow them to hold it, but the moment the riots turn violent we will show zero tolerance," the police official threatened.
The seculars in Jerusalem are also planning a response with a protest expected to be held near the Karta parking lot on Saturday afternoon. The police have approved the participation of 1,000 people, and are preparing for possible clashes with haredi protestors.
In any event, the police promised that the parking lot would remain open. "No one will prevent its opening," vowed a police source.
Ronen Medzini contributed to this report