Pro-Palestinian demonstrators who have vandalised offices and sent threats to MPs have "crossed the line from protest to intimidation", Labour's shadow chancellor Rachel Reeves has said.
The party has been split over its approach to the Israel-Hamas war, with a number of MPs calling for a ceasefire, while the leadership instead demands "humanitarian pauses" to get aid into Gaza.
Politics live: 'Everything on the table' in autumn statement
The division came to a head on Wednesday, when 56 MPs rebelled against the party's position in the Commons to back an SNP amendment calling for an immediate ceasefire - including eight frontbenchers, who quit their posts as a result.
But speaking to Sky News on Sunday, Labour leader Sir Keir Starmer said there still remained "great unity" on his benches as every member was doing "everything they can to alleviate the suffering we are seeing".
Since the vote, some Labour MPs have faced protests at their constituency offices for not backing calls for a ceasefire.
Shadow Welsh secretary Jo Stevens saw her Cardiff office sprayed with the word "murderer" and covered with posters saying she had "blood" on her hands, while large numbers of protesters gathered outside Rushanara Ali's office in Bethnal Green.
Sky News has also been told of cases where MPs have received death threats or had their home addresses posted online.
Asked about the incidents on Sky News' Sunday Morning with Trevor Phillips, Ms Reeves said: "I believe in the right to protest, I don't believe in the right to intimidate, and some of those protests… I believe have crossed the line from protest to intimidation.
"Protesting outside people's homes, putting pressure on them in that way I think is totally unacceptable."
The shadow chancellor said MPs "represent their constituents, but they also listen to all of the evidence", and to attempt to "intimidate" or "put pressure" on them to vote in a certain way was "anti-democratic".
Ms Reeves said she was "hugely concerned" by the incidents, and worried it was putting "good people" off entering politics "because they don't want to put their families through what we are seeing at the moment".
She added: "That would be a real loss to our politics if good people were deterred from going into it.
"So I would urge those people who are conducting those protests, I understand why you call for a ceasefire, but do things in a responsible way and don't intimidate or put pressure in that way on elected representatives or anyone else for that matter."
Her remarks were backed by former Labour adviser Alastair Campbell, who condemned the "nastiness" of the incidents.
Speaking to Trevor Phillips, he added: "We've got such short memories in this country. Jo Cox... [and] David Amis have been killed, and you now see [this] situation because MPs are doing what they're paid to do, which is represent [people] and take part in votes.
"I think Rachel's absolutely right. Protest is fine. Trying to intimidate people and silence them is wrong."