ROME — Dockworkers are threatening Israel with a total block on trade as they vow to support an international flotilla carrying aid to Gaza.

Dockers in the Italian port of Genoa, who sparked massive pro-Palestinian protests in Italy last week with calls to block shipments of goods to Israel, have adopted the Global Sumud Flotilla, an international convoy of 50 boats crossing the Mediterranean to challenge Israel’s blockade of Gaza, that includes crew members from their docks.

The Genoa dockers were joined by dockworkers from all over Europe on Friday and Saturday for talks on blocking arms shipments to Israel. The dockworkers haven’t commented on the outcome of their discussions.

Following suspected drone attacks on the flotilla last week, the dockers have now designated the flotilla as a kind of tripwire for threats of further action, with leaders promising to obstruct shipments linked to Israel if the boats are attacked. The flotilla includes prominent activist Greta Thunberg.

Obstructing all shipments to and from Israel is the only way to force a shift in direction, Riccardo Rudino, a veteran dockworker and leader in the CALP collective of dockworkers, told POLITICO.

“If they attack the flotilla there will be a general strike and, if Israel doesn’t alter course in Gaza, a total trade blockade,” Rudino said. “There is no other path.”

Rudino attracted attention as a protest leader a month ago with a speech that went viral on the internet, warning that if the flotilla is hindered by Israel, they will block “all of Europe,” adding that “not a single nail” will leave Genoa for Israel.

Dockworkers have a long history of obstructing arms shipments going back at least to the Vietnam War, he said. “It seemed impossible with South Africa, but after a total block they freed Mandela and held elections,” Rudino said.

Many people “want to do something to be on the right side of history,” Rudino said. “Blocking things is the people’s weapon. We don’t have tanks; we don’t have missiles — blocking things, at times with our bodies, is the only weapon at our disposal,” he said.

Italian Prime Minister Giorgia Meloni’s government is under increasing pressure to take a tougher line with Israel and recognize Palestinian statehood after it became the prominent issue in regional elections that started Sunday and continue through November.

Italy’s biggest union CGIL has pledged a general strike if the flotilla is attacked.