BRUSSELS, June 16 (Reuters) - A Turkish pro-Palestinian group said on Wednesday it will send another aid flotilla to Gaza next month, again trying to break an Israeli blockade after its last convoy was the target of a deadly Israeli raid in May.

The Foundation for Human Rights and Freedoms and Humanitarian Aid (IHH) told members of the European Parliament it had assembled six ships for the next flotilla and put out an appeal for others to join.

Its last flotilla was intercepted off the coast of Gaza on May 31. Clashes broke out on one of the ships as Israeli commandos boarded it to enforce a blockade, and in fighting that followed Israeli forces shot dead nine Turkish men.

The next flotilla is due to sail in the second half of July, IHH said. The group invited the international media to inspect all goods on board before the convoy sails to demonstrate their commitment to total transparency.

Israel says the IHH has links to Muslim militants, which the group denies.

Richard Howitt, a British member of the European Parliament who organised IHH's press conference at the parliament in Strasbourg, said the European Union had an obligation to ensure respect for humanitarian law and access for the next flotilla.

If this terrible tragedy tips the balance so that the international community finally insists on full and unhindered humanitarian access to Gaza, then some good can still come out of it, he said, referring to the deaths in the last convoy.

Israel has said it is considering softening its blockade in the wake of international condemnation of the flotilla assault. The EU said on Monday it hoped the easing would begin in the next days.

Israel has said it will also hold an investigation into the incident. The probe will be conducted internally with two high-profile foreign observers, rather than being an international inquiry as the United Nations has requested.

The Gaza blockade has been in place since shortly after Hamas, a militant group, won Palestinian elections in 2006. Israel says the measures are designed to stop arms and dual-use equipment reaching Hamas and other militant groups.

Iran, in a move likely to aggravate Israel, said on Monday it was also sending aid ships to Gaza. One left on Sunday and another will leave on Friday carrying food, construction material and toys, Iranian state radio reported.