US President George W Bush has told Palestinian leader Mahmoud Abbas that he will work to realise the vision of two states in the Middle East.
This was the leaders' second meeting in a year
Mr Bush said he supported Mr Abbas's platform of peace but asked him to do more to stop attacks on Israelis.
He also urged Israel to dismantle illegal outposts and stop building new settlements in the West Bank.
The talks come amid worsening relations between Israel and the Palestinians after an attack on West Bank settlers.
Mr Abbas called for an immediate start to the implementation of the roadmap peace plan - widely endorsed by the international community.
All of these things have been said before, says the BBC's Matthew Price in Jerusalem.
But the Americans are positive about the Palestinian leadership - they clearly trust Mahmoud Abbas, and the Palestinian leader also feels that the Palestinians' best chance is to curry favour with the US, as Israel has done over the years, says our correspondent.
The White House talks were the first since Israel left Gaza last month.
Mr Bush told reporters at the joint news conference that the Israeli withdrawal had presented an opportunity for peace.
"The way forward must begin by confronting the threat that armed gangs pose to a genuinely democratic Palestine," Mr Bush said.
He said the Palestinian Authority must "earn the confidence of its neighbours by rejecting and fighting terrorism".
The US leader said he had assured Mr Abbas that "the US would use its influence to help realise a shared vision of two democratic states, Israel and Palestine, living side by side in peace and security".
He said he would appoint a new envoy with a broader mandate to help the search for peace and the rebuilding of the Palestinian economy.
"Achieving peace demands action by all parties," said Mr Bush, before urging Israel not to undertake "any activity that contravenes its roadmap obligations" and prejudices final status talks.
Mr Abbas called on Israel "to join us in a real partnership for making peace".
"The time has come to put an end to the Palestinian-Israeli conflict. The time has come that the Palestinian people will attain the freedom and independence. The time has come to move quickly towards the resumption of permanent status negotiations," said the Palestinian leader.
Mr Abbas urged Israeli leaders to stop settlement expansions, remove roadblocks to facilitate the free movement of Palestinians and to withdraw their troops to positions held before the beginning of the intifada on 28 September 2000.
This was the second time Mr Bush had hosted Mr Abbas at the White House, following the Palestinian leader's visit in May.