Settlers opposing the Gaza pullout and their supporters vowed on Monday to bring Israel to a halt in the run-up to the withdrawals planned for August.
Police arrested 292 protesters who blocked roads and scuffled with police at road junctions as people headed home from work, angering motorists caught in traffic jams.
Six officers were hurt and one demonstrator was injured by a burning tyre, a police spokeswoman said.
Girls, some not yet in their teens, darted into the traffic and lay down in front of cars. Protesters linked arms to block roads before police pulled them away.
Police estimated that about 3000 demonstrators took part in the protests across the country. "This is our struggle against fascism," shouted protesters on the main road from Jerusalem where hundreds gathered.
"Jews do not expel other Jews," chanted others. But polls show most Israelis support Prime Minister Ariel Sharon's plan to dismantle all settlements in Gaza as a way to "disengage" from conflict with Palestinians.
Israeli police officers had to
detain children as well as adults
The plan is also backed by Western countries as a step to revive Middle East peacemaking.
Palestinians welcome the withdrawal, though fear it may be a ruse to keep much bigger settlements in the West Bank. Israel occupied the West Bank and the Gaza Strip in the 1967 Middle East war.
In a related incident, authorities released without charge five Israelis they suspected of planning to fire an anti-tank missile at the al-Aqsa mosque and compound in Jerusalem, the Justice Ministry said on Monday.
The men, described by police as extremists without the means to acquire a missile or the expertise to fire one, had hoped an attack on al-Haram al-Sharif (Noble Sanctuary) would spark violence and stop the planned pullout, police said.
A Justice Ministry official said prosecutors had weighed charging the group with conspiracy to commit a crime, but decided such a case would not hold up in court.
The men were released more than a month ago due to lack of evidence, officials said. Their lawyer said the group fell victim to a sting operation by a security agent.
Palestinian police clash
Meanwhile, rival Palestinian police groups engaged in a brief gunbattle with each other in the Gaza Strip on Monday, in a flare-up that highlighted problems in the force.
Highlighting difficulties with President Mahmoud Abbas's recent security reshuffle, the exchange of fire erupted after police from one branch of the civil police detained a member of another division, members of the force said.
Two policemen were slightly wounded in the shooting, officials declined to comment on the incident.
The Palestinian president last month carried out sweeping reforms of the disparate and often competing Palestinian security services, in an attempt to restore law and order and wipe out corruption.