David Welch, assistant secretary of state for Near Eastern affairs, said on Friday: "The United States believes that the Palestinians should be able to vote everywhere.
"We want to make sure that people feel safe and free to go to vote."
But he also renewed US criticism of the participation in the election of the resistance group Hamas, which is fielding candidates for parliament for the first time.
"The view of the US is that there should be no place in the political process for groups and individuals who refuse to denounce terror and violence, who do not recognise Israel's right to exist and refuse to disarm," Welch said.
He was speaking to reporters after meeting Mahmoud Abbas, the Palestinian president, at his headquarters in the West Bank town of Ram Allah.
Vote to proceed
The Palestinian leader had reiterated his demand that Israel should allow residents of Jerusalem's occupied and annexed eastern sector to participate in the 25 January vote.
Saeb Erikat, the chief Palestinian negotiator, said: "President Abbas confirmed that the elections will go ahead as scheduled and stressed the importance of the participation of Jerusalem residents."
"The United States believes that the Palestinians should be able to vote everywhere. We want to make sure that people feel safe and free to go to vote"
David Welch, assistant secretary of state for Near Eastern affairs
The Palestinian leadership also demanded that Israel "lift its roadblocks and allow free movement of voters and candidates".
Welch and Elliot Abrams, the White House envoy on the Middle
East, had held earlier talks on the Palestinian election with Ehud Olmert, Israel's acting prime minister, according to a statement from his office.
Israel is set to take a final decision on Sunday on whether to allow Palestinians in East Jerusalem to participate in the vote.
Approval is expected to be given after the resignation of four ministers from the right-wing Likud, which opposes the move.
But Israel has already made it clear that it will not allow campaigning in East Jerusalem by Hamas.
Abbas has threatened to cancel the whole election if the approval is not forthcoming.