Officers responded to a report of a crash in the 1900 block of Pulgas Avenue just after 7 p.m., Officer Veronica Barries said.
They arrived to find a Toyota Camry on its side. Two teenage girls had been removed from the car by bystanders and were found on the roadway, she said.
It is not yet known what led up to the crash, but Barries said the Camry collided with a car traveling in the opposite direction, and then hit several parked vehicles.
Menlo Park fire personnel responded and treated the girls at the scene, and they were then transported to a hospital, Barries said. One victim is in stable condition today, but the other is in critical condition, she said.
The person in the other car involved in the collision was treated at the scene and released.
Anyone with information about the crash is asked to call East Palo Alto police at (650) 321-1112 or make an anonymous call to (650) 409-6792. Anonymous tips can be emailed to epatipnow.org.