Israel must provide more freedom of movement in the West Bank and open crossings into the Gaza Strip to avoid driving even more Palestinians into poverty in the wake of Hamas's seizure of Gaza two months ago, the United Nations Mideast envoy said Wednesday. "An elementary constituent of economic development is freedom of movement, and to a very considerable extent that does not exist in the West Bank," Michael Williams said in an interview with The Associated Press and two other media outlets. Williams praised Israel's recent release of Palestinian prisoners and transfer of millions of dollars in frozen tax funds to President Mahmoud Abbas, who set up a government in the West Bank after Hamas took control of Gaza. But Williams said he's "concerned that we haven't seen further steps," and urged Israel to release more prisoners and dismantle illegal settlement outposts in the West Bank. Israel's decision to shut Gaza's borders to all but humanitarian aid in the wake of Hamas's takeover is threatening an already badly damaged economy, and "this shows every sign of getting worse," Williams said. "We do not see how that can be changed short of opening additional crossing points, particularly Karni," Williams said, referring to Gaza's main cargo crossing with Israel. Earlier this month, the UN warned that Gaza will soon become entirely dependent on foreign aid and face "disastrous consequences" if the Hamas-run territory remains sealed off. A Palestinian business group warned that at least 120,000 more Gazans could lose their jobs. Williams said he was concerned by an increase in Israeli killings of militants in Gaza in recent days, as well as by reports of human rights violations by Gaza's new Hamas rulers. Williams began his tenure as UN special coordinator for the Middle East in May. He said he'll be leaving the job in a few weeks, however, to assume the position of Mideast envoy for British Prime Minister Gordon Brown.