Bolton, undersecretary of state for arms control and international security, is also scheduled to visit South Korea for three days from Tuesday before heading to Japan.

The US embassy said Bolton was in Beijing for the second session of the US-China Security Dialogue and that talks with vice foreign minister Zhang Yesui would focus on North Korea and Iran.

A press conference has been scheduled for later Monday.

China hosted trilateral talks with the United States and North Korea in Beijing in April, and has recently stepped up diplomatic efforts to broker a second round.

South Korean officials have indicated talks could resume as early as next month while China Friday said it hoped the talks would take place "as soon as possible".

The United States favours a multilateral format while Pyongyang has insisted on one-on-one talks.

The crisis over North Korea's nuclear ambitions erupted in October when the United States said Pyongyang had admitted running a nuclear program based on enriched uranium in violation of a 1994 nuclear freeze accord between the two countries.

SPACE.WIRE