US house speaker Nancy Pelosi has said members of congress face threats of violence from an “enemy” within, and more money is needed to protect them.

Ms Pelosi’s remarks are an acknowledgment of escalating internal tensions over safety since the attack on the US Capitol earlier this month by supporters of former president Donald Trump.

The California Democrat’s statement came as the acting chief of the Capitol Police said that “vast improvements” are needed to protect the Capitol and adjacent office buildings, including permanent fencing.

Such barricades have ringed the complex since the deadly riot on January 6, but many legislators have long resisted giving America’s symbol of democracy the look of a besieged compound, and leaders have been non-committal about the idea.

Ms Pelosi focused her comments on the anxiety and partisan frictions which have persisted in congress since Trump supporters’ assault on the Capitol, which led to five deaths.

She told reporters she thinks congress will need to provide money “for more security for members, when the enemy is within the House of Representatives, a threat that members are concerned about”.

Asked to clarify what she meant, Ms Pelosi said: “It means that we have members of congress who want to bring guns on the floor and have threatened violence on other members of congress.”

She did not suggest how much money might be needed.

Some legislators who voted for this month’s house impeachment of Mr Trump have reported receiving threats, and initial moves to enhance safety procedures have taken on clear partisan undertones.

Some Republicans have loudly objected to having to pass through newly installed metal detectors before entering the house chamber, while Ms Pelosi has proposed fining legislators who bypass the devices.

Ms Pelosi did not specify who she meant by her reference to an “enemy” within the house, and a spokesperson provided no examples when asked.

First-term Republican representative Marjorie Taylor Greene, who has expressed support for baseless QAnon conspiracy theories, has liked Facebook posts advocating violence against Democrats and the FBI. One post suggested shooting Ms Pelosi in the head.

When asked to comment, Ms Greene sent a written statement accusing Democrats and journalists of attacking her because she is “a threat to their goal of socialism” and supports Mr Trump and conservative values.

Earlier this month, the HuffPost website reported that Andy Harris set off a newly installed metal detector while trying to enter the house chamber and was found to be carrying a concealed gun.

Other Republicans have also talked about carrying firearms, which legislators are permitted to do, though not on the house or senate floors.

Since the attack, the Capitol grounds have been surrounded by barrier fences and patrolled by National Guard troops.

Prosecutors have charged more than 200 people for their roles in the January 6 riot, and others have been arrested after posting threats against members of congress.

The public is barred from carrying firearms on Capitol grounds. Members of congress can keep guns in their offices or transport them on the campus if they are unloaded and securely wrapped.

On Wednesday, the US department of homeland security issued a national terrorism bulletin warning of the possibility of more violence from people motivated by anti-government sentiment after Joe Biden became president.

A senate trial on whether to punish Mr Trump is set to begin next month, following his house impeachment on a charge of inciting the insurrection at the Capitol.

Mr Trump made incendiary remarks to a throng of supporters that day, urging them to march to the building.

Legislators at the time were formally certifying Mr Biden’s election victory, which Mr Trump has repeatedly and falsely attributed to fraud.