WASHINGTON - ON THE eve of a week-long trip to Asia, US Senator John McCain warned on Thursday that North Korea is on 'dangerous ground' with a planned rocket launch and urged China to do more to rein in Pyongyang.

'It argues for, again, increased sanctions on North Korea and increases the urgency of the Chinese becoming far more engaged in this issue,' Mr McCain told AFP in an interview about his travels to Hong Kong, Hanoi, Beijing and Tokyo.

Japan, South Korea and the United States see the North's plan to launch a communications satellite sometime between April 4 and 8 as a disguised test of a Taepodong-2 ballistic missile which could in theory reach Alaska or Hawaii.

Asked whether the possible launch constituted a foreign policy crisis, the Arizona Republican replied: 'I can't say 'crisis,' but it certainly is an enormous challenge.

'On the one hand, North Korea is just trying to get attention. On the other hand, they're getting into very, very serious and dangerous ground,' said McCain, his party's senior member on the Senate Armed Services Committee.

Mr McCain, who lost his bid for the White House to Democratic President Barack Obama in November, said an early March naval confrontation between US and Chinese ships was 'certainly disturbing' but highlighted the importance of Sino-US relations.

'Overall, our relationships with China are still good. We have to continue the dialogue. We have to maintain a careful balance between our respect and advocacy for human rights and our (broader) relationship with China,' he said.

Asked about recent Chinese comments seen as questioning US global economic preeminence, McCain said the Chinese occasionally like to 'rhetorically flex their muscles.'

Asked about relations with Japan, Mr McCain stressed that 'the Japanese remain our steadfast friends in the region' and noted he would be discussing with officials there plans to relocate some 8,000 US troops from Japan to Guam.

Mr McCain's trip opens Sunday in Hong Kong, and will take him to Hanoi, Beijing and Tokyo - as well as on a tour of the USS John McCain destroyer, which is named for his father and grandfather. The ship is based at Yokosuka Naval Base in Yokosuka, Japan. -- AFP