An American politician has been arrested in Hong Kong for carrying a gun into the city, according to public broadcaster RTHK, citing a local court, in what he has called an "honest mistake."

Washington state senator Jeff Wilson was arrested on Saturday at the Hong Kong International Airport and has been charged with possession of a firearm without a license, RTHK reported. He appeared in the Sha Tin Magistrates' Court on Monday and was granted bail, the report added.

The Republican state senator, whose full name is Stephen J. Wilson, said he did not realize he had packed his pistol in his briefcase while he and his wife were traveling for a five-week vacation to Southeast Asia, according to a statement posted on his website.

"It was an honest mistake. And I expect the situation to be resolved shortly," Wilson said in the statement.

Wilson said he "discovered the weapon mid-flight between San Francisco and Hong Kong."

He "did not realize his pistol was in his briefcase when he passed through airport security in Portland, and baggage screeners failed to note it," the statement added.

Wilson said in the statement that when the plane landed in Hong Kong, he "immediately went to customs officials and called their attention to the issue."

CNN has reached out to Portland International Airport, San Francisco International Airport, the Transportation Security Administration and the US Consulate in Hong Kong for comment.

Hong Kong's Customs and Excise Department told CNN via email that it had no comment to make given legal proceedings are underway.

Wilson faces his next court hearing in Hong Kong on October 30, RTHK reported.

Under Hong Kong's strict gun control laws, no one is allowed to possess any arms or ammunition unless they have a license from the Commissioner of Police -- which are only given to police officers, armed security guard services and operators of exclusive shooting range clubs.

Gun violence is very rare in Hong Kong, unlike in the United States where firearms are now the No. 1 killer of children and teens.

In Washington state, open carry is allowed for both long guns and handguns without a license, which means individuals can carry a firearm in many public areas, although private property owners may prohibit firearms on their property. However, a license is needed to carry concealed firearms in the state.

Wilson noted in his statement that his pistol was registered in Washington state and that he holds a concealed pistol license.