Police have erected a fence around the steps of the Ecuadorean embassy in London ahead of an expected news conference by Julian Assange.
A police officer could be heard arguing with a someone who emerged from the embassy about whether the pavement was public or private property.
"Police can deal with it, not you," the officer said. "Let me call the council then," he replied.
More top news
The Metropolitan Police Federation, which set up the official JustGiving site, said it felt a "suitable amount" had been collected.
There is no evidence the Westminster attacker Khalid Masood was associated with so-called Islamic State or al Qaeda, the Met Police said.
Janet Ajao said in a statement: "I do not condone his actions nor support the beliefs he held that led to him committing this atrocity."