Between President Mahmoud Abbas and US officials, the start of so-called proximity talks appear not to have been derailed by Israel's attack on an aid ship and killing of at least nine activists.

On Wednesday, both Abbas and the US deputy treasurer spoke at the Palestinian Investment Conference, stressing the need for talks, while US special envoy to the Mideast George Mitchell addressed the conference Thursday and said talks must go on despite the attack.

Mitchell, who met Abbas after the opening session, said the raid illustrated the need to move forward with peace talks.

Abbas was less clear in his determination to move forward, but made no mention of halting the indirect negotiations. Rather, Abbas again laid out his conditions for peace by highlighting the need to lift the siege on Gaza more than in the past.

"We will not accept that the peace process be a means of evading peace and its dues. The first step toward peace is a complete halt of settlement activities, without conditions, and lifting the siege off Gaza and Jerusalem, and all our cities and villages, as well as committing to the references of peace," he said.

At the same time, Abbas said he would ask US President Barack Obama to make "brave decisions" when he visits Washington on Wednesday.

With US officials promising to take action against any party that spoils the negotiations' atmosphere, Palestinians hope the attack on the flotilla in international waters and the stringent maintenance of the siege on Gaza despite international calls for its immediate halt could force American officials into action.