[Update, 5:21pm] The suspect who allegedly struck and injured a police officer with his car is in custody. According to Bay City News, the suspect was apprehended on the 300 block of Ellis Street around 3:30pm.

[Update, 4:01pm:]

The "shelter in place" and "avoid the area" of Buena Vista Park have both been lifted. #SFPD #SF

— San Francisco Police (@SFPD) October 18, 2017

Just after 12:20pm, a San Francisco police officer was injured in a hit-and-run collision on Turk Street between Van Ness Avenue and Franklin Street.

Now, a hunt is underway for the driver.

According to Sgt. Mike Andraychak, officers assigned to Tenderloin Station were investigating a firearm violation when one of them spotted a suspect in a vehicle who may have been armed.

After a suspect noticed one of the officers, he struck them with his car and fled the scene, police said.

The suspect's vehicle was discovered abandoned near Buena Vista Park in the Upper Haight, nearly two miles from the scene of the collision. A shelter-in-place order has been issued as authorities comb the neighborhood. Police have not released the suspect's description.

The officer, who has not been identified, was injured seriously. After the incident, he was transported to San Francisco General Hospital. As of this writing, he is "in surgery after receiving significant injuries," reports ABC7's Lyanne Melendez.

Shelter in place ordered for SF homes near Buena Vista Park as police search for man who ran down officer at Turk & VanNess @12:20. #ABC7now pic.twitter.com/mk72y0eh1u

— Dan Noyes (@dannoyes) October 18, 2017

Chinese Immersion School on lockdown and shelter in place in Buena Vista Park area in San Francisco. Police officer injured. MUNI delays. https://t.co/ZuRXbORJMn

— Michael Fullam (@bombasticbunnee) October 18, 2017

SFMTA warns riders to expect delays in the area.

ATTN: Due to #SFPD activity near the Buena Vista area, the 6, 7, 24, 33, 37, & 43 may see delays through that area.

— SFMTA (@sfmta_muni) October 18, 2017

We'll update this story as more information is available.

Update, 10/19, 8:54am:  The suspect was taken into custody at around 3:30pm yesterday, police officials reported. 

More details about the incident have come out: Tenderloin Station officers were conducting a firearms violation investigation, as they believed that the suspect in the vehicle had a firearm. 

Once the suspect became aware of the officers, he drove away and struck the officer on the bicycle. 

The officer is now out of surgery and in the intensive care unit.

Although an arrest was made, officials are asking anyone with information about this incident to contact SFPD via the department's anonymous tip line at 415-575-4444, or text TIP411 with "SFPD" at the start of the message.