Video: 'If you are watching this, Israel has blocked our aid ship'
The Israeli navy on Sunday seized a ship that was aiming to break the siege of Gaza and deliver supplies of aid and medicine to the coastal enclave, which was devastated by last summer's war.
The Swedish boat, the Marianne, which set off on Friday from Greece, was intercepted by Israeli authorities in international waters and escorted to the Israeli port of Ashdod early on Monday.
Sailors on the mission, known as the Freedom Flotilla, have recorded videos asking for international help, after they say Israel violated international law by intercepting a peaceful vessel.
Three other vessels in the flotilla turned back after the interception of the Marianne, according to reports.
Fears were raised after Israel threatened to take action against the flotilla, which is modelled on an earlier mission that ended in tragedy in 2010 when Israeli forces stormed an aid ship, leading to the deaths of ten activists.
In 2012, volunteers on the second Freedom Flotilla aboard the Estelle were tasered and beaten with clubs by Israeli forces after they boarded the vessel in international waters.