* Clash deepens doubt about peace chances in US-led talks
* Israel says Palestinians fail to prosecute own militants
* Abbas denies Palestinians dodging security commitments
By Dan Williams
TEL AVIV, Jan 28 (Reuters) - Israel and the Palestinians disagreed sharply on Tuesday over the effectiveness of security measures by the regional Palestinian administration in the Israeli-occupied West Bank, deepening doubt about peace prospects in U.S.-brokered talks.
Foreign powers have been helping build up Palestinian President Mahmoud Abbas's security services in the West Bank to prevent militant attacks on Israelis and ward off any challenge from breakaway Hamas Islamists who control the Gaza Strip.
Relative calm is considered important to any chance of Israel and the Palestinians striking a long elusive deal for a Palestinian state in the West Bank and Gaza, next to Israel. But the two sides remain far apart on key terms.
Israeli Defence Minister Moshe Yaalon poured scorn on the commitment of the Palestinian Authority, which exercises limited self-rule in the West Bank under interim peace deals, to follow through in moves against Palestinian militants.
"We counted 1,040 cases that were handled by the Palestinian security services in 2013. How many of them went to trial? Zero," Yaalon said at an international conference hosted by Tel Aviv University's INSS think-tank.
In the same period, Yaalon said, Israel had arrested some 3,000 Palestinians, many of whom were later imprisoned.
Yaalon is a stalwart of Prime Minister Benjamin Netanyahu, who balks at Palestinian calls to remove Jewish settlements from the West Bank. Yaalon ratcheted up acrimony this month with an Israeli newspaper quoting him as dismissing U.S. Secretary of State John Kerry, the peace patron, as "messianic".
After Yaalon's speech, the conference aired a videotaped interview with Abbas, who said he would stand firm on his statehood demands and could hold Hamas to a peace accord.
He did not say how. Hamas, which spurns permanent co-existence with Israel, won a 2006 Palestinian legislative election and a year later ejected Abbas's faction from Gaza.
Asked what his administration was doing to maintain West Bank calm, Abbas said: "All the security forces are devoted to performing their duty to prevent arms smuggling and their use within the Palestinian Authority or Israel."
"This is the utmost challenge that the security forces are dealing with. It is not a secret that this is done with the full cooperation of the Israeli and the American security apparatuses," Abbas said.
A U.S. official briefed on the West Bank situation was hard put to explain the disagreement between Abbas and Yaalon.
"It's true that we haven't seen trials" of Palestinian suspects held by Abbas's administration, the official told Reuters on condition of anonymity. But, the official said, that did not mean there was no Palestinian security enforcement.
Asked if that meant Abbas's forces might be dealing with suspects away from public view, the U.S. official said "yes".
With the peace talks at a virtual standstill, two surveys, by the INSS and the Palestinian Center for Policy and Survey Research (PSR), released on Tuesday found that 67 percent of Israelis and 70 percent of Palestinians do not believe a permanent peace accord can be reached.
The INSS poll surveyed 1,200 Israeli Jews, while 1,270 Palestinians were interviewed by the PSR in the West Bank and Gaza Strip. Both polls have a margin of error of 3 percent.
With a nine-month target date set by Washington expiring in late April, disputes holding up peacemaking have included Israel's insistence on keeping a military and settler presence in the Jordan Valley, the future Palestine's eastern border.
Abbas said Palestinians must control their borders as part of final statehood, but that he was prepared to partner up with Israel as it withdraws, as well as with foreign peacekeepers.
"I think NATO is the suitable third party for this mission," he said, repeating a proposal for a role by the U.S.-led alliance that he has voiced in the past. (Editing by Jeffrey Heller and Mark Heinrich)