The Californian State Capitol was evacuated after police were warned of a "credible threat".
The threat came from a suspect who had the night before shot at a hospital, police later revealed.
In a memo from Secretary of the Senate Erika Contreras, staff were told to stay home if they had not already come in.
The letter read: "“The California Highway Patrol (CHP) has notified the Senate of a threat they consider to be credible involving the Capitol.
“The CHP and security partners are present in higher numbers in the Capitol area, and are alert of the situation.”
It later was revealed the suspect behind the threats had shot a gun from his vehicle while driving through two Sacramento suburbs on Wednesday night, lodging bullets in the wall of a hospital and a commercial building, but thankfully injuring no one.
The suspect is still at large, the California Highway Patrol said.
The planned session meeting of lawmakers was postponed for 45 mibutes until 9.45am local time and moved to a different room.
The Roseville Police Department said in a statement it received a call late Wednesday about someone shooting a gun from a vehicle while driving through Citrus Heights and, later, a suspect shooting towards a hospital in Roseville from the parking lot.
Two bullets were lodged in the exterior of the building, the department said.
“At this time, we believe this suspect may also be related to an incident at the State Capitol,” police said in a statement.
Staff were also told: "All Senate staff who have not yet reported to work in the Capitol, LOB and 1021 0 Street building should remain home and work remotely.
"Those who are already in their offices should remain in place until further information becomes available."
The Assembly canceled its session, said John Ferrera, chief of staff for assembly member Cecilia Aguiar-Curry.
Staffers were told to “remain situationally aware and report any suspicious activity,” said a memo from chief administrative officer Lia Lopez.
Assembly member Liz Ortega said: "My staff and I are safe. There has been a credible threat to the Capitol. CHP and law enforcement are taking precautions to ensure everyone’s safety."
Outside the Capitol on Thursday business appeared to go on as usual with people walking around the park that surrounds the building.
Assembly speaker Anthony Rendon and senate pro tem Toni Atkins said in a joint statement that they relocated the Senate and ended the Assembly session early “out of an abundance of caution.”
“We apologize for the adjustments and interruptions to the members of the public who planned to come to the Capitol today to make their voices heard,” they said. “In this situation, we must put everyone’s safety and security first. We encourage everyone to stay alert and stay safe.”
