US President Donald Trump has said he wants to expand America's nuclear arsenal to put his country "top of the pack."

In an interview with the Reuters news agency, President Trump said that the United States has fallen behind in its atomic weapons capacity - and complained about Russian deployment of a cruise missile in violation of an arms control treaty.

He also warned that he is against what he called a "one-sided" new deal with Russia that would cap the deployment of nuclear warheads.

He said he would raise the issue with Russian President Vladimir Putin if and when they meet.

Meanwhile speaking at the CPAC conference in Washington DC, White House chief of staff Reince Priebus said Mr Trump has made a good start to his presidency:

“Protecting the sovereignty of the United States, putting a wall on the southern border, making sure that criminals are not part of our process - these are all things that 90% of Americans agree with,” he said.

President Trump also turned his attention to China which he said could solve the national security challenge posed by North Korea "very easily if they want to."

His comments will ratchet up pressure on Beijing to exert more influence to stop Pyongyang's increasingly threatening actions.

He said that while he welcomed China stopping coal imports from North Korea, Beijing needed to put more pressure on Pyongyang.

Speaking from behind his desk in the Oval Office, he also declared himself "very angry" at North Korea's ballistic missile tests and said accelerating a missile defence system for US allies Japan and South Korea was among many options available.

Additional reporting from IRN ...