Palestinian President Mahmoud Abbas vowed on Tuesday to take a tough stance in talks with Israel and said he would tell a U.S. envoy that Israel's Gaza offensive proved it was not intent on peacemaking.

In his first news conference in the Palestinian territories since Israel launched its 22-day offensive on December 27 that killed some 1,300 people in Gaza, Abbas also said he would back international efforts to prosecute Israel for war crimes.

"We will do all we can to prove Israel committed crimes that would make your skin crawl," Abbas said, referring to the Geneva Conventions. "We want the world to give us justice for once.

"Israel does not want peace, otherwise it would not have done this. We need to understand this and tell it to those coming from Europe and America. Israel wants to waste time to strengthen facts on the ground with settlements and the wall."

Ten Israeli soldiers and three …