Barclays bank branches in England and Scotland have been covered in red paint and had windows smashed as part of protests by a pro-Palestine group.
Up to 20 buildings have been targeted, according to the group Palestine Action.
It said the protests were carried out to “demand the bank divests from Israel’s weapons trade and fossil fuels”.
A spokesperson for Barclays said: “While we support the right to protest, we ask that campaigners do so in a way which respects our customers, colleagues and property.”
In Bristol, the windows of a city centre branch of Barclays Bank were smashed and red graffiti sprayed over the building.
Meanwhile, in Edinburgh, rocks inscribed with the names of Palestinians killed in the conflict were thrown at a Barclays building, the protesters said.
City of London police said three men, aged between 34 and 45, had been arrested in connection with criminal damage at the Barclays on Moorgate on Monday morning.
It is one of several branches in the capital to have been targeted.
Among them were ones in St John’s Wood, north London, Croydon, Richmond, south-west London, and Peckham and Croydon in south London.
Meanwhile, branches in Stockport and Bury, both in Greater Manchester, and Preston, Lancashire, have been adorned in red paint and damaged.
The protesters also struck in Glasgow, Brighton, Exeter, Sheffield, Northampton, Birmingham and Solihull, Palestine Action said.
Shut the System, a recently launched underground climate movement, partnered with Palestine Action’s underground division to launch the attacks, both activist groups confirmed.
According to the groups, targeted actions will continue until Barclays stops investing in certain companies.
A spokesperson for Barclays said the bank “provides vital financial services to US, UK and European public companies that supply defence products to NATO and its allies”.
“The defence sector is fundamental to our national security and the UK government has been clear that supporting defence companies is compatible with ESG considerations,” the spokesperson added.
“Decisions on the implementation of arms embargos to other nations are the job of respective elected governments.”
During its 7 October attacks in southern Israel, Hamas killed about 1,200 people and took some 251 people hostage.
Some 116 remain in the Palestinian territory, including 41 the army says are dead.
On Saturday, the Hamas-run health ministry said the death toll in Gaza stood at 37,084 people.