The top American diplomat Rex Tillerson is heading to East Asia, where he'll stop in Japan, South Korea and China.

He's making his first official tour of the region at a time of heightened tension over North Korea's nuclear and missile programmes.

Donald Trump promised while campaigning for the presidency to get tough on Pyongyang's ally, China.

Now the question is - will Tillerson follow through?

Al Jazeera’s State Department correspondent Patty Culhane reports from Washington DC.

US & Canada, Politics