Mayor Michael R. Bloomberg said yesterday that the city seized nearly 650 cars driven by drunken drivers this year in a continuation of a policy begun in 1999 by Mayor Rudolph W. Giuliani.

Since the program was started, 5,460 cars have been taken from drivers charged with being drunk, although 14 percent of the vehicles were returned when the owners accepted treatment. The policy has withstood several legal challenges.

Mr. Bloomberg also said yesterday that the Police Department would operate 36 drunken-driving checkpoints in all five boroughs over the holiday weekend, a practice the city often employs during the summer. The principal entry points to the city will also be monitored; those areas are already on high alert because of vague threats of terrorism.

"Simply put, drunk driving is selfish, criminal and it kills, and we are not going to tolerate it," Mr. Bloomberg said, citing 1,971 drunken-driving-related accidents in the city last year, resulting in 34 deaths. "If you are thinking about driving drunk, don't do it. Because we will take your car, and send you to jail. Make no mistake about it."

Mr. Bloomberg, who usually reads his prepared statements with little fanfare and scant emotion, took on an unusually scolding tone yesterday as he flipped through enlarged examples of four public service advertisements that the city is also beginning.

Two depict smashed cars, the other two, a driver being arrested.

Mr. Bloomberg has said on numerous occasions how moved he was by the death of Andre Lahens, an emergency medical technician who was hit in April by a drunken driver while on an emergency call that turned out to be a false alarm. The mayor said yesterday that he would "never forget" seeing Mr. Lahens in his hospital bed, and he has often spoken of the plight of the wife and four children the man left behind.