U.S. envoy Dennis Ross headed back to Washington Tuesday without a deal on a West Bank pullout, but a top adviser to Prime Minister Benjamin Netanyahu said progress was made.

In four days of talks with Netanyahu and Palestinian leader Yasser Arafat, Ross was unable to make headway on persuading Israel to agree to a U.S. proposal for a troop withdrawal from 13 percent of the West Bank.Ross said the stalemated peace talks were beginning to "diminish the hopes that people have for seeing a very different Middle East and for building and achieving peace."

In the West Bank, a defiant Netanyahu went before Jewish settlers to declare that Israelis would not be made "suckers" in the peace process.

"We are not suckers," Netanyahu told high school students in Maale Adumim, a settlement east of Jerusalem. "A situation in which we will give and not receive is not acceptable. Israel cannot give and give and not get anything back in return from the other side."

Also in the West Bank, Palestinians chanting "Death to America" stoned Israeli troops on Monday.

Israeli troops fired tear gas and metal pellets to disperse hundreds of protesters in the West Bank towns of Bethlehem, El Bireh and Ramallah. Several Palestinians were injured.

Palestinian police, meanwhile, rounded up several supporters of the Islamic militant group Hamas for questioning about the explosion of a car, reportedly rigged with 110 pounds of dynamite.

The car - apparently intended to be used in an attack in Israel - exploded Sunday in an industrial zone of the West Bank town of Ramallah, killing one Palestinian. The blast's force reduced the car to a ball of twisted metal and leveled the garage it was hidden in.

David Bar-Illan, a top adviser to Prime Minister Netanyahu, said the explosion showed that the Palestinians were not doing enough to fight terrorism, Israel's key demand.

Bar-Illan said Netanyahu had "flatly rejected" an American proposal for Israel to withdraw its troops from 13 percent of the West Bank, and he added that Israel had made no counterproposal.

Netanyahu has said Israel can give up no more than 9 percent of the West Bank and has denied Israeli media reports that he had made a compromise offer of 11 percent.