GENEVA, Switzerland - UN human rights chief Navi Pillay on Monday condemned Israel's use of military force against a flotilla of aid ships as "disproportionate", after up to 19 people were killed when the vessels were stormed.
The UN High Commissioner for Human Rights joined calls for an "immediate and credible" inquiry into the interception and urged Israel to lift its blockade of the Gaza Strip.
"We need to establish exactly what happened. However, nothing can justify the appalling outcome of this operation, which reportedly took place in international waters," Pillay said in a statement.
"I unequivocally condemn what appears to be disproportionate use of force, resulting in the killing and wounding of so many people attempting to bring much-needed aid to the people of Gaza, who have now been enduring a blockade for more than three years."
According to Israel's Channel 10 television, 19 passengers were killed when Israeli naval forces stormed the ships, although the army gave a toll of 10.
The vessels were on the last leg of a high profile mission by pro-Palestinian activists to deliver some 10,000 tonnes of supplies to Gaza as part of a protest against Israel's blockade of the territory since 2007.
Pillay had earlier told the UN Human Rights Council that she was shocked that the convoy was "met with violence".
She reiterated her concerns about the impact of the Israeli blockade on human rights in the Palestinian territory ruled by the Islamist Hamas movement.
"The blockade lies at the heart of so many of the problems plaguing the Israel-Palestine situation, as does the impression that the Israeli Government treats international law with perpetual disdain," she said.
"If the blockade had been lifted, there would be no need for flotillas like this," Pillay added.
Israel had said the attempt to break the Gaza blockade, imposed since Hamas was elected, was illegal and warned that it would intercept the ships and detain the activists.
It labelled the convoy a media stunt and a provocation, insisting the humanitarian situation is stable in Gaza despite reports to the contrary from aid agencies.
Islamic states at the Human Rights Council condemned the military intervention and called on Israel to immediately release the boats and those on board.
"We strongly condemn today's Israeli attacks on the boat convoy carrying humanitarian aid and supplies to the people of occupied Gaza," Pakistani diplomat Marghoob Saleem Butt said on behalf of the Organisation of the Islamic Conference (OIC).
"This is yet another example of Israeli disregard of all international norms and laws," he told the Human Rights Council.
"We demand that Israeli authorities immediately release all the boats and arrested people and take action against those responsible for these attacks and killing," he added.
Israel has accused activists on some of the boats of initiating the deadly bloodshed by attacking its military boarding force with live fire, knives and clubs.
Saudi Arabia called Israel's move a "very serious violation of all international law."