US warns North Korea against 'provocations'
The United States and Japan have warned North Korea not to carry out a new nuclear test.
US President Barack Obama and Japanese Prime Minister Yoshihiko Noda held a press conference after talks in Washington.
Mr Obama says North Korea's "old pattern of provocation" will not be tolerated.
He says the communist north's recent actions, including a failed rocket launch, would "only serve to deepen Pyongyang's isolation".
Prime Minister Yoshihiko Noda is the first Japanese leader to visit Washington in three years.
Mr Noda says there is a great possibility that Pyongyang will carry out its first nuclear test since 2009.
The visit comes as the two countries agreed to relocate 9,000 US marines from Okinawa to Guam.
More than 20,000 US troops are stationed in Japan, leading to local resentment.
The leaders say they will continue to work towards an early resolution on this issue and have pledged to strengthen defence ties.