SAN DIEGO (CNS) - Seventeen motorists were arrested for drunk driving Thursday night and Friday morning at a checkpoint set up downtown by San Diego police, California Highway Patrol and the San Diego County Probation Department, authorities said.

The checkpoint was in operation in the East Village from 11 p.m. Thursday until 3 a.m. today to coincide with the St. Patrick's Day Shamrock block party in the Gaslamp Quarter, said San Diego police Officer Mark McCullough.

Some 20,000 people are estimated to have attended the annual event.

Police said 2,325 vehicles passed through the checkpoint in the 1400 block of G Street. Officers screened 762 drivers. Ten of the 27 who were screened for drunk driving passed the field sobriety test. Nineteen vehicles were impounded, according to McCullough.

The checkpoint was made possible by a California Office of Traffic Safety grant.