Two men armed with loaded handguns were arrested Thursday near the Philadelphia convention centre where an ongoing vote count could decide the presidential election, police said.

Joshua Macias, 42, and Antonio LaMotta, 61, travelled from the Virginia Beach, Virginia, area in a Hummer and did not have permits to carry the weapons in Pennsylvania, police said.

They were arrested after the FBI in Virginia relayed a tip about their plans to Philadelphia police. Officers stopped the men about a block from the vehicle, Philadelphia Police Commissioner Danielle Outlaw said.

Macias had a .40-calibre Beretta handgun inside his jacket, LaMotta had a 9mm Beretta in a holster and an AR-style rifle and ammunition were found inside the vehicle, Outlaw said. Authorities initially said that the rifle did not have a serial number but later said that it did.

A silver Hummer with Virginia license plates was parked Friday at the location where police say they found the men's vehicle. It was adorned with an American flag, a window sticker for the right-wing conspiracy theory QAnon and a fresh parking ticket.

A woman with the men was not arrested, Philadelphia District Attorney Larry Krasner said.

Macias and LaMotta, both of Chesapeake, Virginia, remained in police custody on Friday and were awaiting arraignment on state weapons charges: carrying a concealed firearm without a license and carrying a firearm on a public street.

Information on lawyers who could speak on their behalf wasn't immediately available.

Macias and LaMotta's arrests drew outsized attention amid heightened tensions over the undecided presidential race, but officials cautioned against reading too much into them.

There was no indications that anyone else was involved or that the men are members of an extremist group, Krasner said. He said there have been no reported incidents of violence election-related violence in the city.

Macias had posted a video to Facebook showing him outside the convention centre wearing a T-shirt for "Veterans for Trump," a group for which he was a founding member.

"We are in a fight for America as we know it. We're not going to give up our freedoms," he said in the video. He also said they want to make sure "legitimate" votes were counted and repeated a false belief among some Trump backers about the ballot counting process.