Updated June 01, 2017 07:27:20

Photo: Police Chief Peter Newsham says he believes a "potential disaster" was avoided. (AP: Matthew Barakat)

A 43-year-old man has been arrested at President Donald Trump's International Hotel in Washington DC after police found a high-powered assault rifle and ammunition in his car, a discovery they believe has prevented a "potential disaster" in the US capital.

"We're going to do a thorough examination if we can get the motive as to why this guy was coming to the District of Columbia armed with these weapons," Secret Service agent Mike Ball said.

"I can tell you this, I was very concerned."

Brian Moles of Pennsylvania was taken into custody shortly after checking into the Trump International Hotel a few blocks from the White House, Metropolitan Police Chief Peter Newsham told a news conference.

A tipster had told the Pennsylvania State Police Moles was traveling to Washington with the weapons, and the information was passed on to the Secret Service and Washington police, Mr Newsham said.

"I believe that the officers and our federal partners and in particular the tipster coming forward averted a potential disaster here in our nation's capital," Mr Newsham said.

Moles was arrested without incident, the chief said.

Asked about reports that Moles had made threatening remarks, Mr Newsham said his motive was under investigation and there was not enough information to charge him with making threats — the nature of the threats has not been divulged.

Photo: The Trump International Hotel in Washington DC has been a focal point for anti-Trump protests. (AP: Alex Brandon)

The Secret Service said in a statement it also was investigating the incident but said that no-one under its protection was ever at risk.

Police had been told Moles had a Glock 23 pistol and a Carbon 15 Bushmaster rifle, an incident report said — officers saw one of the guns in his car and found a second firearm in the glove compartment.

He also had 30 rounds of 7.62mm ammunition and 60 .223-caliber rounds, the report said.

He was charged with two counts of carrying a pistol without a license and possessing unregistered ammunition.

Mr Trump's hotel on Pennsylvania Avenue, housed in a landmark former post office, has become a focal point for protests against the Republican president since he took office in January.

Edinboro Police Chief Jeff Craft said by telephone that Moles had no criminal record in the western Pennsylvania town and was not known to police.

Wires/ABC

Topics: world-politics, donald-trump, united-states

First posted June 01, 2017 07:23:28