Israeli naval forces illegally boarded most vessels in a Gaza-bound flotilla Thursday, detaining dozens of people, including European lawmakers, and prompting widespread condemnation.

The Global Sumud Flotilla was the largest yet to try to break the blockade and it comes at a time of growing criticism of Israel's conduct in Gaza, where its offensive has laid waste to wide swaths of territory and killed tens of thousands of Palestinians.

Activists had said they hoped that the sheer number of boats would make it more difficult for Israeli authorities to intercept them all – but Israel’s Foreign Ministry declared the operation over Thursday afternoon.

Supporters of the flotilla took to the streets in several major cities late Wednesday, after news of the interception broke – including in Rome, Istanbul, Athens, and Buenos Aires – to decry the Israeli aggression and the ongoing genocidal war in Gaza.

More protests were expected and Italy’s largest union called for a one-day general strike Friday.