District police, enforcing the city's ban on protesting farmers' vehicles on the Mall, evicted about 60 remaining campers, pick-ups and trailers yesterday under a threat of impoundment.

Backed by tow trucks and a 100-man motorbike squad, Civil Distrubance Unit officers twirling nightsticks walked through the nearly empty American Agriculture Movement encampment at noon to deliver their ultimatum.

A few angry farmers who vowed to keep their campers "at all costs" on the Mall relented after receiving a one-hour reprieve from the mayor's office.

By 2:30 p.m., all but four farm vehicles were on their way to new camps at Greenbelt Park in Maryland and to several sites clustered at Rte. 1 and the Beltway in Virginia. Police impounded the four vehicles that were left behind -- a tractor trailer, a pick-up, a school bus and an abandoned tractor -- but more than 150 tractors are still left on the Mall.

D.C. Deputy Police Chief Robert Klotz said he would permit about 100 tractors to stay "a few more days" before taking any further action. Klotz agreed last week to let a symbolic group of 50 tractors remain indefinitely near the Capitol.

Several farmers called the police show of force "unwarranted." One Nebraska farmer confronted by a mass of walking policeman called to a companion sitting in a nearby Winnebago, "You want to seen a sight you'll never forget, get out here."

Klotz said he would immediately begin removing much of the Metrobus barricade used to corral the farmers on the Mall during their month-long protest. The remaining tractors will be blockaded into an area east of Third Street at Constitution Avenue. Klotz said the police plan no extra security for the tractors after this evening.