The United Nations' Human Rights Council decided on Wednesday to send an independent fact-finding mission to investigate Israel's deadly attack on an aid flotilla bound for the Gaza Strip.

The decision was included in a resolution the council passed, which also condemned the "outrageous attack" by Israel.

At least nine people were killed and more than 30 injured in Monday's Israeli commando raid on the Gaza-bound aid convoy.

The resolution also called on Israel to ensure the unimpeded provision of humanitarian assistance, including food, fuel and medical treatment to the Gaza Strip, which has been under a Israeli blockade for more than three years.

The resolution, proposed by Palestine as well as Pakistan and Sudan representing Islamic and Arab countries, was passed by a vote of 32 countries in favor, three countries against and nine abstentions. The United States, Italy and the Netherlands voted against it.

Its adoption followed a two-day "urgent debate" on the Israeli raid on the six-ship flotilla, which has drawn criticism from around the world.