Donald Trump has defended pro-gun activists and attacked Virginia Democrats over efforts to pass gun control laws ahead of a rally that is expected to be attended by neo-Nazis and white supremacist extremist groups.

Authorities in Richmond, Virginia’s capital, have warned of “credible threats of violence” amid fears a pro-gun rally, which has been billed a peaceful event to defend Second Amendment rights, could become a repeat of the violent Charlottesville rally which saw three deaths in 2017.

“Your 2nd Amendment is under very serious attack in the Great Commonwealth of Virginia,” Mr Trump tweeted, in reference to the constitutional right for Americans to keep and bear firearms.

“That’s what happens when you vote for Democrats, they will take your guns away.”

On Wednesday, Virginia’s governor Ralph Northam declared a state of emergency ahead of Monday’s event and warned law enforcement agencies had seen evidence of “extremist rhetoric” similar to the kind seen before the Charlottesville rally.

Charlottesville one year on Show all 15 1 /15 Charlottesville one year on Charlottesville one year on Mary Grace, from Durham, North Carolina, walks through the downtown mall area August 11, 2018 in Charlottesville, Virginia. Charlottesville has been declared in a state of emergency by Virginia Gov. Ralph Northam as the city braces for the one year anniversary of the deadly clash between white supremacist forces and counter protesters over the potential removal of Confederate statues of Robert E. Lee and Jackson. A "Unite the Right" rally featuring some of the same groups is planned for tomorrow in Washington, DC. Getty Charlottesville one year on Chris Jessee (R) hands out placards to people visiting downtown Charlottesville as the city marks the anniversary of last year's 'Unite the Right rally' in Charlottesville, Virginia, USA, 11 August 2018. On 12 August 2017, a bloody clash between white supremacists and counterprotestors in Charlottesville left three people dead and dozens injured Getty Charlottesville one year on A member of the Virginia State Police waits outside the park where a statue of Confederate Gen. Robert E. Lee is located August 11, 2018 in Charlottesville, Virginia. Charlottesville has been declared in a state of emergency by Virginia Gov. Ralph Northam as the city braces for the one year anniversary of a deadly clash between white supremacist forces and counter protesters over the potential removal of Confederate statues of Robert E. Lee and Jackson. A "Unite the Right" rally featuring some of the same groups is planned for tomorrow in Washington, DC Reuters Charlottesville one year on A woman displays a shirt ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. Reuters Charlottesville one year on A sign reading "Strength, which was taken down at the request of police officers, hangs by the statue of Civil War Confederate General Robert E. Lee, ahead of the one-year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018. Reuters Charlottesville one year on Law enforcement arrives ahead of the one year anniversary of 2017 Charlottesville "Unite the Right" protests, in Charlottesville, Virginia, U.S., August 10, 2018 Reuters Charlottesville one year on A vendor displays wares on the mall as State Police lock down the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., Saturday, Aug. 11, 2018. The Governor has declared a state of emergency in Charlottesville AP Charlottesville one year on A Police bike patrol takes a break in the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., Saturday, Aug. 11, 2018. State and local authorities framed the weekend's heightened security as a necessary precaution. AP Charlottesville one year on State Police arrest a local resident, John Miska, in the locked down downtown area in Charlottesville, Va., Saturday, Aug. 11, 2018. Miska purchased razor blades, which are banned items, in a downtown drugstore. On the the anniversary of white supremacist violence, state and local authorities framed the weekend's heightened security as a necessary precaution. AP Charlottesville one year on State Police escort local resident, John Miska, red hat, after he was arrested in the locked down downtown area in Charlottesville, Va., Saturday, Aug. 11, 2018. Miska purchased razor blades, which are banned items, in a downtown drugstore. On the the anniversary of white supremacist violence, state and local authorities framed the weekend's heightened security as a necessary precaution. AP Charlottesville one year on A group Anti-fascism demonstrators, march in the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., Saturday, AP Charlottesville one year on A group anti-fascism demonstrators march in the downtown area in anticipation of the anniversary of last year's Unite the Right rally in Charlottesville, Va., AP Charlottesville one year on People receive first-aid after a car accident ran into a crowd of protesters in Charlottesville, VA on August 12, 2017. A vehicle plowed into a crowd of people Saturday at a Virginia rally where violence erupted between white nationalist demonstrators and counter-protesters, witnesses said, causing an unclear number of injuries AFP/Getty Charlottesville one year on Alt-right rally members in Lee Park in Charlottesville, VA on Saturday August 12, 2017 White nationalist 'Unite the Right' rally, Charlottesville, USA Rex Charlottesville one year on A counter protester who got hit with a stick by alt-right member covered with blood on his face in Lee Park in Charlottesville, Rex

The state of emergency has temporarily banned firearms and other weapons on Capitol grounds, where the demonstration is set to take place.

Three alleged members of a neo-Nazi hate group were arrested in Maryland on Thursday over reports they were planning to bring firearms to the event, according to the FBI.

Despite concerns over potential violence, Virginia’s senate passed bills late on Thursday to require background checks on all firearms sales, limit handgun purchases to one a month and restore local governments' right to ban weapons from public buildings and other venues.

The gun legislation comes after Democrats took full control of the state legislature for the first time in a generation in November, when candidates made passing stronger gun control laws a central theme of their campaign.

On Friday, the Supreme Court of Virginia denied a request to block the state of emergency and kept the ban on firearms in effect.

Mr Northam welcomed the ruling, which he said was the “right decision”.

“I took this action to protect Virginians from credible threats of violence,” the governor said.

“These threats are real - as evidenced by reports of neo-Nazis arrested this morning after discussing plans to head to Richmond with firearms.”

He added: “I will continue to do everything in my power to keep Virginians safe.”

Gun-control activists have reported a growing number of online death threats due to the push for legislation ahead of the rally.

The mother of Heather Heyer, the civil rights activist who was killed while protesting against neo-Nazis in Charlottesville, told The Independent she is concerned about an “incitement of violence” ahead of the event in Richmond.

“I just think everyone needs to take a moment and breathe, but I think we’re past that point,” Susan Bro said.

“To anybody planning violence: stay the hell away from Richmond,” she added.

Virginia’s legislature is expected to pass further gun control laws, including universal background checks, a ban on assault rifles and “red flag” laws that would allow courts and local law enforcement to remove guns from people who are seen as a risk to communities.

Supporters have said these laws would help decrease the number of deaths from gun violence each year.

However, gun-rights activists have argued that the legislation goes against the constitutional right to possess firearms.

In 2017, Mr Trump was widely-criticised for initially saying there were “fine people on both sides” in the clashes at Charlottesville, which saw neo-Nazis and white supremacists fighting with civil rights groups and anti-fascist activists.