White House trespasser killed at US courthouse after attacking sheriff with a knife

A man who once jumped a fence at the White House has been killed at a US court house after he slashed a police officer with a knife.

Curtis Smith, 34, sliced the deputy sheriff, injuring his left arm and hand, at a security entrance to the Chester County Justice Center in Pennsylvania, CNN reported.

Another officer pulled out a firearm and shot Smith, who received first aid at the scene, before he was taken to a local hospital where he was pronounced dead.

The officer involved in the attack was also treated at the scene for knife wounds.

The incident occurred around 11.50am local time Tuesday (1.50am AEST today).

“Curtis Smith, from Coatesville, came directly into the justice centre and pulled out a knife, and attacked a deputy sheriff, slashing him,” District Attorney Tom Hogan said.

A witness said Smith had verbally threatened the officer during the attack.

“He said, ‘I’m gonna get ya, I’m gonna get ya,’ he ran right through the door, right through security, and I hear, ‘POP, POP’. And it was the sheriff shooting him,” Reiley Aikman told ABC News.

Police said the officer who opened fire is being investigated.

In March, Smith scaled a fence on the grounds of the White House, and walked along a sidewalk before he was approached and apprehended by Secret Service agents.

However, he avoided conviction and struck a deal outside of court after being charged with unlawful entry.