The following are details of how the surge is affecting countries, compiled by Reuters reporters around the world:

UNITED STATES

Jewish advocacy group the Anti-Defamation League reported last week that antisemitic incidents had risen by about 400% in the two weeks following the Oct. 7 attack, compared with the same period last year.

Government officials met American-Jewish leaders on Monday to discuss steps to counter what a White House official described as an alarming uptick in reported instances of antisemitism on university campuses.

After a man screaming "Free Palestine" and "Kill Jews" attempted to break into a Jewish family's home in Los Angeles on Oct. 25, Mayor Karen Bass said police would continue stepping up patrols in communities throughout the city.

CANADA

Prime Minister Justin Trudeau spoke on Oct. 17 of a "scary rise" in antisemitism in Canada, citing incidents at a Jewish high school in Toronto as well as escalating inflammatory language online.

BRAZIL

Jewish leaders have noticed a rise in antisemitic discourse online, and incidents such as graffiti defacing a synagogue in Rio de Janeiro. No instances of physical threats or assaults have been reported.

"We are very concerned. We have increased the security of our institutions," said Ricardo Berkiensztat, executive president of the Jewish Federation of the State of Sao Paulo.

He said he had seen comments online such as "Hitler didn't finish, he should have finished killing Jews".

BRITAIN

London's police force said there had been a 14-fold increase in incidents of antisemitism since the Oct. 7 attack.

The Community Security Trust, which collates reports of antisemitism in Britain, said the number of incidents in the three weeks following the attack was the highest for any three-week period since it started collecting data in 1984.

FRANCE

Interior Minister Gerald Darmanin said on Monday that since Oct. 7 there had been 819 antisemitic acts. That compares with a figure of 436 for the whole of 2022.

Darmanin said there had been 414 arrests in connection with this trend.

GERMANY

A survey by a civil society observatory, the RIAS, found a 240% year-on-year increase in antisemitic incidents in the period of Oct. 7-15.

NETHERLANDS

No official figures are available yet, but Eddo Verdoner, national coordinator for combating antisemitism, said a sharp rise had been observed and anxiety was high in the Jewish community.

He said Jewish parents had reported their children had been harassed at school, with comments such as "Hamas were right" and "they should have done it earlier" directed at them.

SOUTH AFRICA

The number of antisemitic incidents in October is nine times higher than the average recorded for that month over the past decade, according to David Saks, associate director of the South African Jewish Board of Deputies.

In one incident, a woman who shared a link to information about a protest calling for the release of Israeli hostages being held in Gaza was abused online, including a post that said "we'll come for her babies next".

RUSSIA

After an angry crowd stormed an airport in the Dagestan region searching for Jews to harm after a plane arrived from Tel Aviv, the president of Russia's Federation of Jewish Communities called on the authorities to harshly punish the organisers.

Rabbi Alexander Boroda said the airport riot "undermined the basic foundations of our multi-cultural and multi-national state".

CHINA

No figures are available on antisemitic incidents. On Oct. 13, a staff member of the Israeli embassy in Beijing was assaulted and a suspect was arrested.

Chinese social media is awash with antisemitic content, including posts suggesting the Nazi Holocaust was justified and likening Jews to parasites, vampires or snakes.

A foreign ministry spokesperson said the law prohibited the use of the internet to propagate hate speech, but there were no discernible efforts by the authorities to curb antisemitic activity online.

(Reporting by Andrew MacAskill, Layli Foroudi, Julia Harte, Chen Lin, Maytaal Angel, Andrew Osborn, Carien du Plessis, Steven Grattan, Wa Lone, Thomas Escritt and Stephanie Van Den Berg, Writing by Estelle Shirbon)