The stevedores at the port in Fos-sur-Mer outside Marseille have refused to load crates of links used to assist the rapid fire of bullets aboard the cargo vessel, the CGT trade union said.

Links are small metal pieces, used to connect machine gun bullets and allowing rapid bursts of fire. There has been concern in media and among rights groups that they have likely been used against civilians in the Gaza Strip.

Christophe Claret, leader of the dock workers in the port, said they had been notified that the ship was due to be loaded on Thursday with the material.

"We managed to identify it and set it aside," he told AFP, emphasising that once dockers refuse to load a shipment, no one else can do it for them. The other containers for the ship will all be loaded.

According to the union, the cargo is 19 pallets of links manufactured by the Marseille-based company Eurolinks.

The CGT said the move made clear its refusal to "participate in the ongoing genocide orchestrated by the Israeli government." Leading rights groups have accused Israel of committing genocide in its military campaign, a charge vehemently rejected by the government.

- 'Humanism is not for sale' -

Contacted by AFP, Eurolinks did not respond to a request for comment. The Port of Marseille-Fos had no comment.

"We are very proud of this action led by our comrades and which is part of the CGT's long internationalist tradition for peace," CGT secretary general Sophie Binet told reporters in the eastern city of Strasbourg on Thursday.

"It is unacceptable that CGT dockers should be the ones forced to uphold the fundamental principles of international law and French values. The government must immediately block all arms deliveries to the State of Israel," she said.

The move was also welcomed by hard-left and left-wing leaders in France.

"Humanism is not for sale," said Socialist Party leader Olivier Faure.

According to the investigative website Disclose, which had access to maritime data, two other such shipments between Fos-sur-Mer and the Israeli port of Haifa took place on April 3 and May 22.

French Defence Minister Sebastien Lecornu had stated at the time that these parts exported by the Marseille company would be "re-exported" through Israel and not used by the Israeli army.

The latest war started after Hamas fighters attacked Israel on October 7, 2023.

The attack resulted in the deaths of 1,218 people, mostly civilians, according to an AFP tally based on official Israeli figures. Of the 251 hostages seized during the attack, 55 remain in Gaza, including 32 the Israeli military says are dead.

Israel's military offensive on Gaza since October 2023 has killed 54,677 people, mostly civilians, according to the health ministry in the occupied Palestinian territory, while the United Nations said on May 30 the territory's entire population of more than two million people was at risk of famine.