International tensions over antisemitism have erupted after two Israeli embassy staff were shot dead at a Jewish museum in Washington DC.
The FBI is investigating the background of the alleged gunman, who shouted "free Palestine" as he was arrested.
FBI director Kash Patel called the attack an "act of terror".
Police detained the alleged shooter, 30-year-old Elias Rodriguez of Chicago, at the scene. He has been charged with two counts of first degree murder, which could attract the death penalty.
"We're going to continue to investigate this as a hate crime and a crime of terrorism," interim US attorney for DC Jeanine Pirro said.
"And we will add additional charges as the evidence warrants."
Israeli Foreign Minister Gideon Saar blamed European criticism of his country's stepped-up Gaza offensive for the attack, claiming "a direct line connecting antisemitic and anti-Israeli incitement to this murder".
"This incitement is also done by leaders and officials of many countries and international organisations, especially from Europe," he said.
French foreign ministry spokesperson Christophe Lemoine called the accusation "completely outrageous and completely unjustified".
The killings took place just outside the Capital Jewish Museum late on Wednesday, local time. The venue, 1.6 kilometres from the White House, was hosting a social event for young professionals and diplomatic staff.
[map]Israeli Prime Minister Benjamin Netanyahu cited "the terrible price of antisemitism" and decried "wild incitement against the State of Israel".
Soon after the shooting, US President Donald Trump — who spoke with Mr Netanyahu on Thursday — posted on social media that the attack was clearly antisemitic and such killings had to stop.
Israel identified the victims as Yaron Lischinsky, an Israeli citizen, and Sarah Lynn Milgrim, a US employee of the embassy, and said they were a couple.
Mr Lischinksy had just bought an engagement ring and was preparing to propose.
After the shooting, Israeli embassies around the world immediately stepped up security.
FBI Deputy Director Dan Bongino posted on social media that investigators were "aware of certain writings allegedly authored by the suspect" and he hoped to soon have updates regarding their authenticity.
Mr Bongino's statement appeared to refer to a manifesto signed with the suspect's name that was posted to an anonymous X account shortly before the shooting.
The manifesto condemned Israel's killing of tens of thousands of Palestinians since the October 2023 Hamas attacks and discussed the morality of "armed" action.
Video from the crime scene on social media showed a bearded man in a jacket and white shirt shouting "free, free Palestine" as he was led away.
The attack came days after the museum was awarded a grant to boost security, as antisemitism surges worldwide in the wake of Israel's devastating invasion of Gaza.
Tensions have risen in the United States and many other countries over the ongoing Israeli assault on Gaza, with pro-Palestinian activists decrying what they say is the intolerable human cost of the military offensive.
Foreign Minister Penny Wong said the Australian government was shocked and appalled by the killings.
"There is no place for antisemitism in the world," she wrote on X.
"It must be denounced and condemned."
Britain, France and Canada — who have stepped up their criticism of Israel's actions — were also among nations to condemn the shootings.
But Mr Netanyahu accused those three countries of emboldening militants, saying "they want Israel to stand down and accept that Hamas's army of mass murderers will survive, rebuild and repeat the October 7 massacre".
In a video message, he said the countries "think that they're advancing peace. They're not".
The day after the shootings, mourners gathered at the museum in Washington to sing and pray.
"We have to find a better way to a better future for Israelis, for Palestinians, for American Jews, for Muslims, for all of us," said Hadar Susskind, head of the progressive New Jewish Narrative group.
"Obviously the war is awful," mourner Gil Livni said.
"[But] antisemitism, I feel it every day … people that I thought were my friends showing that they are antisemitic. It's become the norm."
Israeli ambassador Yechiel Leiter told reporters at the scene that he rejected any "insinuation that antisemitism is rising because of Israel's defence of its country".
"Hamas declared war, Israel is responding," he said.
The targeted event was an annual reception hosted by the American Jewish Committee for young Jewish professionals and the Washington diplomatic community.
Mr Lischinsky was a researcher at the Israeli embassy, while Ms Milgrim worked for its public diplomacy department, according to their LinkedIn profiles.
Mr Lischinsky was Christian, according to The Times of Israel newspaper, where he had previously worked as a blogger. He also held a German passport.
ABC/wires
