The Israeli military says its troops have boarded and seized an aid ship heading for Gaza, but there was no violent confrontation.
The action comes after Israel warned that its forces would board the Gaza-bound aid ship -- the "Rachel Corrie" carrying some 19 people -- if it did not go to a port in southern Israel.
UN High Commissioner for Human Rights Navi Pillay responded to the news by calling the Gaza blockade "illegal" and saying it "must be lifted."
Israel has faced a storm of criticism since its deadly May 31 raid on a humanitarian-aid flotilla similarly bound for Gaza.
Israeli Defense Forces spokeswoman Avital Leibovich told CNN the action was a "compliance boarding" with the consent of those aboard, and that it took place in international waters.
Leibovich added that "there was no resistance or violence on the boat."
Organizers of the private aid ship previously said they would not resist in any encounter with Israeli forces.
Satellite communication with the "Rachel Corrie" was said to be blocked, presumably by Israeli authorities. Nobel peace prize winner Mairead Maguire was aboard the ship.
Israel had ordered the ship, which was some 50 kilometers off the Gaza coast, to divert to the port of Ashdod. Organizers of the private aid ship had previously said they will not resist in any encounter with Israeli forces.
CNN reported that the cargo would be off-loaded and its cargo screened and checked against a list of items banned under the Israeli embargo.
Israel's Gaza blockade "is illegal and must be lifted," echoing an earlier appeal from UN Secretary-General Ban Ki-moon for an immediate end to the Israeli cordoning.
"International humanitarian law prohibits starvation of civilians as a method of warfare and...it is also prohibited to impose collective punishment on civilians," Pillay said.
Staunch Israeli ally the United States has suggested the blockade of long-suffering Gaza cannot continue in its present form.
"We are working urgently with Israel, the Palestinian Authority, and other international partners to develop new procedures for delivering more goods and assistance to Gaza," a spokesman for the White House National Security Council said in a statement, according to Reuters. "The current arrangements are unsustainable and must be changed. For now, we call on all parties to join us in encouraging responsible decisions by all sides to avoid any unnecessary confrontations."
Turkey, whose citizens bore the brunt of the deaths reported in the May 31 boarding, has warned that Tel Aviv risks losing an important regional partner and its standing in the international community.
Deputy Turkish Prime Minister Bulent Arinc told parliament this week that "new cooperation will not start and relations with Israel will be reduced" in the wake of the flotilla deaths.
