Updated

Israel is "prepared for the worst" in a showdown with pro-Palestinian activists seeking to breach Israel's sea blockade of Gaza but still hopes they will drop the plan, a Cabinet minister said Wednesday.

Information Minister Yuli Edelstein called on organizers to change course and deliver their cargo of medicine and construction materials to Gaza via an Israeli port. They rejected that option Wednesday.

The 10 ships could sail yet this week. Israel has said it will not allow them to reach Gaza. Greece is the flotilla's base of operations, but activists won't disclose the exact location of the boats because of security concerns.

Israel has enforced a Gaza border blockade since the Islamic militant group Hamas seized the 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.

Israel has since eased some Gaza land border restrictions, allowing most consumer goods to enter from Israel.

Edelstein portrayed the flotilla organizers as misguided, arguing that Gaza does not suffer a humanitarian crisis.

A U.N. official in Gaza disagreed. "We see very little impact on the ground and on the life of the Palestinian refugees living in the Gaza Strip" over the past year, said Milina Shahin. "The humanitarian situation is the same."

Israel continues to limit the import of cement, steel and other construction materials, allowing such shipments only for internationally supervised projects in Gaza. Israel argues that construction materials could be diverted by Hamas for military use.

Most exports from Gaza are still banned.

An Israeli human rights group, Gisha, on Wednesday criticized both the Israeli government and the flotilla organizers, saying in a statement that the focus on humanitarian aid by both sides is "infuriating and misleading."

Edelstein said Israel is not taking any chances with the flotilla this time.

"This is our lesson from last year," he told reporters. "That's why we are trying to get prepared for the worst."

Israeli Defense Minister Ehud Barak told Israel's Channel 2 TV that this year's flotilla appears more peaceful than last year's, but "we cannot discount the possibility that there will be a small group of extremists who will use violence, even firearms."