The prime minister has suggested there may be a case for banning some protests, following calls for a suspension of pro-Palestinian marches.
Asked if he wanted tougher policing of language used during marches, or if he wanted to stop some protests altogether, Sir Keir Starmer told BBC Radio 4's Today programme: "I think certainly the first, and I think there are instances for the latter."
Sir Keir said he would always defend the right to protest but he was concerned about the "cumulative" effect of repeated marches on the Jewish community.
It comes after two Jewish men, Shloime Rand and Moshe Shine, were stabbed in Golders Green, London, on Wednesday.
Essa Suleiman, 45, has been charged with three attempted murders.
He is also accused of attacking Ishmail Hussein, a man he had known for around 20 years, in Southwark, in London, on Wednesday.
The Golders Green victims have been discharged from hospital after sustaining serious injuries in the attack, which was declared a terror incident by police.
There have been a string of violent incidents targeting Jewish people in recent months.
A review into public order and hate crime legislation - commissioned by the government after two Jewish people were killed in an attack outside a Manchester synagogue last year - was expected to report back in February, but has not yet been published.
The government's independent reviewer of terrorism legislation Jonathan Hall KC called this week for a "moratorium" on pro-Palestinian marches because it was currently "impossible" for them not to incubate antisemitism.
Chief Rabbi Sir Ephraim Mirvis also called for a temporary ban, telling the BBC they had contributed to a "tone of Jew hatred" in the UK.
Asked about these calls, Sir Keir said: "I think it's time to look across the board at protests and the cumulative effect."
"In relation to the repeated nature of the marches, many people in the Jewish community have said to me, it's the repeat nature, it's the cumulative effect.
"Now, I accept that, which is why we intend to deal with cumulative effects."
Pushed on whether some protests needed to stop altogether, Sir Keir said: "We need to look at what further powers we can take."
Regarding concerns about linking protests to attacks on Jews, he said he would "defend the right of peaceful protest very strongly and freedom of speech".
"I'm not saying, of course, that there aren't very strong, legitimate views about the Middle East, about Gaza. We all have deep concerns about it."
A campaign group which helped to organise a number of the marches, Stop the War Coalition, said it condemned "all forms of antisemitism and racism" but that it was "wrong" to connect the marches to attacks on Jews.
Green Party leader Zack Polanski said Sir Keir was "using the pain and fear of Jewish people to threaten further authoritarian restrictions on peaceful protest".
"This would be the worst response to the attacks in Golders Green and would just produce more division when it's the job of responsible leaders to bring people together", he said.
Jeremy Corbyn's Your Party also warned the response to the "abhorrent" attacks should not restrict civil liberties.
The Liberal Democrats said protests should only go ahead when they are "safe", with police scrutinising each case, and must not then be "hijacked" by people engaging in antisemitic abuse or inciting violence against Jews.
Officers should be "out in force" with the training, equipment and confidence to make arrests quickly, said the party's home affairs spokesperson Max Wilkinson MP. "We absolutely support the police taking strong action to keep British Jews safe."
Conservative leader Kemi Badenoch said it was "time to ban these marches" or attacks like those seen in Golders Green and Manchester would continue.
"They were given the benefit of the doubt, but it is quite clear they are being used as a cover for promoting violence and intimidation against Jews".
Reform UK's home affairs spokesperson Zia Yusuf said the prime minster's "weak words come far too late" and pledged a "zero-tolerance approach to protesters inciting violence" to ensure British Jews could live without fear.
"Under Tory and Labour governments these marches have not been policed properly, with a blind eye turned to chants that incite violence or support terrorist organisations," he said.
Police in England and Wales can restrict protests in some circumstances, such as by stipulating their route or when they must end, or apply to ban them outright if such restrictions are not enough to prevent "serious public disorder".
Such requests require the approval of the home secretary and are not regularly used. In March, the government approved a police request to ban London's Al Quds Day march - marking the first time a protest march had been banned since 2012.
Meanwhile, Sir Keir said chants like "globalise the intifada" - based on an Arabic word for uprising - were "very dangerous" to the Jewish community and should be prosecuted.
"If you are on a march or a protest where people are chanting, 'globalise the intifada', you do have to stop and ask yourself, why am I not calling this out?" he said. "Why am I on a march where this is the chant?"
The term intifada came into popular use during the Palestinian uprising against Israeli occupation of the West Bank and Gaza Strip in 1987.
Jewish groups have described it as a call for violence against Jewish people, while pro-Palestinian groups have said it is a call for peaceful resistance to Israel's occupation of the West Bank and actions in Gaza.
In December, the Metropolitan Police and Greater Manchester Police said they would arrest those using it in chants or on placards following the attack on a Jewish festival on Australia's Bondi Beach.
The prime minister - who was heckled with chants of "Jew harmer" when he visited Golders Green on Thursday - was also asked about criticism from the Jewish community that the government had not done enough to keep them safe.
He said he recognised "the depth of feeling" and that many Jews were "feeling very scared", saying: "I'm not here to criticise that in any way."
But he said it was "not right to say we haven't done anything", pointing to enhanced police security in areas like Golders Green which had "been in place for some time".
The government has also announced increased funding for protecting Jewish communities.
Update 2 May: This story has been amended to reflect that the suspect Essa Suleiman has been charged with the attempted murder of Ishmail Hussein.
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