US and French activists chant slogans as they hold placards after a news conference about an international flotilla to blockaded Gaza, in Athens.

Jerusalem - Organisers of a flotilla of pro-Palestinian activists seeking to break the blockade of Gaza say Israel has sabotaged a second ship.

An activist tells Israel's Army Radio that the engine of an Irish ship was damaged while in port.

Earlier this week, activists said Israel damaged the propeller of a Swedish ship in the Greek port of Piraeus.

Israel has not commented on the allegations.

About 10 ships are due to set sail this week from Greece. It is not clear whether the damage to the boats will hold things up.

Israel imposed a naval blockade after anti-Israel Hamas militants overran the Palestinian territory in 2007.

Last year, an Israeli raid on a similar flotilla killed nine activists on a Turkish vessel. Each side blamed the other for the violence. - Sapa-AP