The Israeli Navy has intercepted a new Gaza-bound aid ship Rachel Corrie following its earlier attack on the Gaza Freedom Flotilla, pro-Palestinian activists say.
"They are being followed," Greta Berlin of the Free Gaza group told Reuters on Saturday.
Berlin said earlier that the Rachel Corrie was some 55 km (35 miles) west of Gaza in the Mediterranean.
The new ship, scheduled to arrive in the Gaza Strip on Saturday, was seeking to break a three-year-long blockade of the coastal sliver.
There are no immediate reports of violence on board the Irish ship.
The activists have already rejected an Israeli demand to unload its cargo in the Israeli port of Ashdod, adding that they would not resist Israeli forces in case of an attack.
The Rachel Corrie is carrying some 750 tons of aid including medical and school supplies, and 15 people including Nobel Peace Prize laureate Mairead Maguire and former UN assistant secretary general Denis Halliday.
The ship is named after Rachel Corrie, a US activist killed in 2003 as she tried to prevent an Israeli military bulldozer from razing a Palestinian home in Rafah.