Israeli Prime Minister Benjamin Netanyahu has pledged to restore unity to the country, where divisions have widened over his government's judicial reform programme.
Meanwhile, police fired water cannon at protesters blocking a motorway in Tel Aviv.
At least 92 people were arrested throughout the country, including several leaders of the protest movement.
Former Israeli prime minister Ehud Barak described the arrest of Shikma Bressler, a protest organiser and physicist at the Weizmann Institute of Science, as "dictatorship in action".
Demonstrators also surrounded a home where key politician Simcha Rothman was visiting.
Mr Rothman is an architect of the judicial reforms, and one of their most fervent backers.
He was eventually escorted from the premises under police protection.
People protesting against the proposed reforms fear they will increase the power of politicians over the courts and are a threat to Israeli democracy.
Many countries in the international community have also raised concerns about the reforms.
Tens of thousands protested in Tel Aviv and other cities, according to estimates by Israeli media.
Similar-sized crowds have taken to the streets on other occasions during routine protests over the past few months since the proposals were introduced.
Police were particularly concerned about a march through the ultra-Orthodox city of Bnei Brak.
Residents lit fireworks and aimed them at protesters, but no injuries were reported.
Before the march, President Isaac Herzog pleaded for calm and called on all sides to “prevent violence and lower the flames as much as possible”.
Ultra-Orthodox politicians form a key block in Mr Netanyahu's coalition.
The community's exemption from military service and large state handouts are a major source of contention in Israeli politics.
Mr Netanyahu, in a televised address, said he was determined to advance the reforms but wanted to reach a solution acceptable to supporters and critics of the proposal.
"The opponents of the reform are not traitors. Partisans are not fascists," he said.
"I will do everything, everything, to bring calm and end division among the people," he said, including objections from high-level officials.
Defence Minister Yoav Gallant, who has supported calls to pause the legislative process for talks with opponents, cancelled a planned address to the nation on Thursday evening after a meeting with Mr Netanyahu, shortly before the premier went on TV.
Politicians earlier on Thursday approved legislation restricting grounds for declaring a premier unfit for office, a move opposition chief Yair Lapid called "a personal law" to protect Mr Netanyahu, who is on trial for corruption, which he denies.
Protests continue in Israel - in pictures
-
Israelis demonstrate during 'Day of Resistance' against the government's judicial overhaul, outside the US consulate in Tel Aviv. Reuters -
Israeli naval reservists and volunteers in Haifa use flares to demonstrate during the Day of Resistance. Reuters -
A demonstrator stands with an Israeli flag on an overpass above others march in Tel Aviv. AFP -
Israelis demonstrate in Bnei Brak. Reuters -
Demonstrators in Tel Aviv. AFP -
A woman rides with a cart-cycle with children in Tel Aviv. AFP -
Prime Minister Benjamin Netanyahu's nationalist coalition government is pressing on with its judicial overhaul. Reuters -
Israelis demonstrating outside the US Consulate in Tel Aviv. Reuters
Last week President Herzog, who holds a largely symbolic role, expressed concern over the deepening rift in society and presented a proposed compromise. The government rejected it.
"Anyone who thinks that a genuine civil war, with human lives, is a line that we could never reach has no idea what they are talking about," Mr Herzog said.
On Thursday one demonstrator, Nadav Golander, 37, warned of a dictatorship if the government presses forward with its agenda.
Many demonstrators carried Israeli flags and some clashed with officers.
Police reported at least 10 arrests in Tel Aviv over alleged public order offences.
Thousands also rallied in Jerusalem outside Mr Netanyahu's home, as well as in the northern city of Haifa and southern Beersheba, Israeli media reported.
Justice Minister Yariv Levin announced the reforms in January, days after Mr Netanyahu's government, a coalition with ultra-Orthodox Jewish and extreme-right allies, took office.
Mr Netanyahu and his allies say the proposed changes are necessary to reduce the powers of the Supreme Court, which they claim has become politicised.
Members of the opposition have refused to negotiate with the coalition, demanding a complete freeze on all legislation related to the judicial reform.
In a call on Sunday with Mr Netanyahu, US President Joe Biden voiced support for a compromise and stressed the importance of "genuine checks and balances", the White House said.
German Chancellor Olaf Scholz urged Mr Netanyahu to reconsider Mr Herzog's compromise proposal.
On Monday, the ruling coalition presented an amended version of a key element of the overhaul, ahead of votes planned before parliament goes into recess next week.
Other pieces of legislation in the reform package would wait until the summer session to enable "real dialogue" with the opposition, coalition parties said in a joint statement.
The new version of a bill to change the way judges are selected would put more politicians and members of the judiciary in the judicial appointments panel than the initial text.
Opponents have accused Mr Netanyahu of trying to use the reforms to quash possible judgments against him, an accusation he rejects.
Politicians on Thursday voted by 61 to 47 to approve an amendment to one of Israel's Basic Laws, the country's quasi-constitution, specifying the conditions for temporary removal of a prime minister.
The previous version of the law stated that a premier could be declared incapacitated, but did not specify on what grounds or lay out the necessary steps.
The amended legislation requires a request by the prime minister, or a government vote backed by a three-quarter majority of ministers, and only for mental or physical health reasons.
The law "de facto limits the possibility of declaring a prime minister incapacitated to exercise their functions", said Guy Lurie, a researcher at the Israel Democracy Institute in Jerusalem.
"Reasons other than those specified in the amendment will no longer be admissible."
Some opposition figures and civil society groups have argued for Mr Netanyahu to be declared unfit to serve, due to his continuing trial.
He denies the charges of bribery, fraud and breach of trust.
