A US Capitol police officer was killed and another injured in an attack on Friday. The incident occurred after a man rammed a car into a security checkpoint outside the Capitol building. Police said the suspect stepped out of the vehicle armed with a knife and was shot by them. The US Capitol complex was soon placed on lockdown following the deadly attack. "A suspect entered the north barricade of the Capitol this afternoon. He rammed his car into two of our officers, hit the north barricade barrier. The suspect was armed with a knife, he didn’t respond to verbal comments. He tried launching an attack on police officers who then fired upon the suspect. Both officers were rushed to hospitals, one succumbed to his injuries," a police officer said. This comes less than three months after a mob assault on Congress over presidential polls. The Capitol was on security lockdown, with no one allowed to enter or exit buildings.