Officials said Mr Bosworth would not offer North Korea any new incentives
The US special representative to North Korea, Stephen Bosworth, has begun a three-day visit to Pyongyang to find out if it will return to nuclear talks.
The visit is the first high-level contact between US President Barack Obama's administration and Pyongyang.
US officials said Mr Bosworth would try to find out whether Pyongyang was ready to return to the six-party talks on its nuclear disarmament it left in April.
But they said Pyongyang would not be offered any new incentives to do so.
North Korea has been pushing for direct talks with the US.
But the US has said bilateral talks would only serve as a precursor to a return to six-party negotiations.
A senior White House official said Mr Bosworth's first visit to North Korea was "not intended to be an extended bilateral engagement".
"The purpose of their mission is to determine whether the North Koreans are ready and willing to return to the six-party talks and return to a serious discussion of the denuclearisation of the Korean peninsula," the AFP news agency quoted the unnamed official as saying.
The official told reporters at a news conference in Washington DC that Mr Bosworth was "definitely not carrying any additional inducements" to encourage them to return to the talks.
Oct 2006 - North Korea conducts an underground nuclear test
Feb 2007 - North Korea agrees to close its main nuclear reactor in exchange for fuel aid
June 2007 - North Korea shuts its main Yongbyon reactor
June 2008 - North Korea makes its long-awaited declaration of nuclear assets
Oct 2008 - The US removes North Korea from its list of countries which sponsor terrorism
Dec 2008 - Pyongyang slows work to dismantle its nuclear programme, after a US decision to suspend energy aid
April 2009 - Pyongyang launches a rocket carrying what it says is a communications satellite
25 May 2009 - North Korea conducts a second nuclear test
5 August 2009 - Former US President Bill Clinton visits to help secure the release of two detained US journalists
6 October 2009 - North Korea tells China it may be willing to return to six-party talks
"We don't intend to reward North Korea simply for going back to doing something that it had previously committed to do," he said.
North Korea pulled out of the talks in April, after the UN Security Council condemned its testing of long range missiles.
Mr Bosworth is due to hold talks with North Korea's top leaders but it remains unclear whether he will meet the country's leader, Kim Jong-il.
Analysts have dampened expectations ahead of the visit, suggesting the most that can be hoped for is a general promise that the North would return to talks sometime
But the BBC's Michael Bristow in Seoul says that despite the pessimism, the visit itself is a mark of progress.
North Korea had said it would never return to the talks, but there is a chance the meeting with Mr Bosworth could persuade them to start talking again, says our correspondent.
On a recent visit to Beijing, South Korea and Japan, Barack Obama and his hosts all affirmed the importance of getting North Korea back into talks.
Mr Bosworth's first talks with North Korea are expected to last three days. He will then make stops in Seoul, Beijing, Tokyo and Moscow before returning to the US.