Ban wants former New Zealand Prime Minister Geoffrey Palmer, a maritime law expert, to head the panel, which would include Israeli, Turkish and US representatives, the Foreign Ministry official said. He spoke on condition of anonymity because Ban has not announced details of his proposal.

The push for an international inquiry puts Israel under further pressure to explain how its attempt to stop the aid ship from breaching a blockade of Hamas-ruled Gaza turned deadly.

The outrage over the deaths has prompted calls from many nations, including the United States, for at least a partial lifting of a blockade that Israel says is necessary to isolate Hamas, which rules Gaza.

On Saturday, Israel hijacked another aid ship. All 19 activists and crew were to be deported Sunday, Interior Ministry spokeswoman Sabine Haddad said.

UN officials in Israel had no information on Ban's planned investigation, which the secretary-general first indicated he would pursue on Wednesday.

The UN's humanitarian chief, John Holmes, on a visit to Australia, said the UN "was pursuing the question of an independent investigation of these events. And also, we want to try to help if we can if the conditions are right, to make sure that the aid reaches those it was intended for."

An inner Cabinet of senior ministers was to meet later Sunday to discuss Ban's proposal and other options for investigating the deadly raid, the Foreign Ministry official said.

Israel has resisted an external investigation into the raid, saying it is capable of investigating itself. It also resists subjecting its soldiers to an international inquiry.

International involvement in the inquiry, however, could ease the diplomatic strains with Turkey, once a close ally but now a vehement critic.

Eight Turks and a Turkish American were killed in the May 31 raid, and a preliminary autopsy report released by Turkey on Saturday said they were shot a total of 30 times.

Israel said its forces acted in self-defense against people it described as extremists.

The Turkish ship was part of a six-vessel international aid flotilla and was the only one of the boats where violence broke out between Israeli troops and passengers.

The grave diplomatic fallout from the raid has Israel reconsidering its Gaza blockade, imposed in 2007 after Hamas took over the territory. Israel argues that a blockade is necessary to keep weapons and other military components out of the hands of Hamas. It had also hoped the blockade would weaken the Islamist group by deepening the privation in already impoverished Gaza.

In practice, however, the blockade's efficacy has been badly weakened by a network of border tunnels between Gaza and Egypt that has served as a conduit for both weapons and commercial goods. And it has only deepened animosity among Gaza's 1.5 million residents toward Israel rather than provoke anger against Hamas.

The United States, Israel's closest ally, on Friday joined other nations in saying the blockade in its current form is not sustainable — adding further pressure on Israel to find another way to keep weapons out.

Mideast envoy Tony Blair told Israel's Army Radio on Sunday, "We need a policy that protects completely Israel's security ... but we need also to try and help the people there (in Gaza)." Blair represents the Quartet of Mideast negotiators — the US, UN, European Union and Russia.