Israel has yet to honour a commitment to halt Jewish settlement expansion and begin dismantling some outposts, the US ambassador has said.
Israel promised to freeze settlement activity
Ambassador Dan Kurtzer said Washington was still waiting for Israel to deliver on promises it made last year.
"This is something Israel undertook to do and... we expect them to be fulfilled," he told Israeli army radio.
Israel's army has meanwhile released figures showing a sharp fall in suicide attacks by Palestinian militants.
The number of attacks is said to have dropped by 75% since January, compared to the same period last year.
"Israeli forces thwarted no less than 103 suicide bombing attempts over the past six months," Israeli media quoted army officers as saying.
They reported the arrest of around 2,000 Palestinians during the same period on suspicion of involvement in militancy, as well as the capture of "58 potential suicide bombers".
Responding to the news, Israeli Defence Minister Shaul Mofaz said Palestinian "terrorist organisations are still extremely motivated but their operational capacity has markedly decreased".
Mr Mofaz also said the Palestinian Authority, headed by Yasser Arafat, had stopped funding the al-Aqsa Martyrs' Brigade, a militant group with ties to Mr Arafat's Fatah movement, and had made a "certain effort" to thwart militant attacks.
The call by the US' Israel ambassador, Daniel Kurtzer, for Israel to honour earlier pledges regarding the settlements comes as Prime Minister Ariel Sharon's government seeks to push ahead with its plan to remove Jewish settlers from the Gaza Strip.
Israeli tactics against the intifada appear to be working
Ambassador Kurtzer's warning relates to settler outposts built recently on the West Bank, which Israel had promised to uproot under the US-backed "roadmap" peace plan.
Mr Sharon had promised to put a freeze on all fresh settlement activity in the area while uprooting all illegal structures built since he came to power in 2001.
An Israeli official told the Associated Press action against the settlements was being hampered by pending lawsuits brought by the settlers.
Settlement watchdog body, Peace Now, claims more Jewish settlements have been erected since the "roadmap" agreement, than have been dismantled.
Separately, a survey of Israel's Jews has shown a majority wants the government to encourage the country's Arab citizens to leave.
Ethnic Arabs make up a fifth of the population in the predominantly Jewish state.
Almost 64% of the people polled by Haifa University for the Maariv newspaper said they would support the government if it tried to resettle Israel's Arabs abroad.
A further 55% said the Israeli Arabs posed a security risk and about 45% said they should not be allowed to elect members of parliament.