About 150 tractor-trailers - singly and in clusters - were moving along approaches to Washington early today in a continuation of an impromptu protest against high diesel fuel prices that was marshaled on highways to the north by truckers using CB radios.

At 2 a.m., a large convoy of about 100 trucks was orbiting the city on the inner loop of the Capital Beltway at about 20 miles an hour, jamming all three lanes. It was unclear whether the truckers would attempt to bring their protest to Washington's streets or disband to complete deliveries of goods they were carrying to other cities.

State police in Virginia and Maryland were stationed at beltway exits to prevent the truckers from taking to local thoroughfares.

The protest, which at one point included as many as 200 trucks, originated yesterday afternoon as truckers used their CBs to talk to one another in New Jersey, Delaware and northern Maryland, according to police and several truckers.

The 18-wheel rigs jammed traffic on the John F. Kennedy Memorial Highway (Rte. 95) in Maryland north of Baltimore, then tied up traffic around Baltimore by stopping at the Harbor Tunnel toll station.

Despite some apprehension by law enforcement officials that the entire convoy was headed for Washington, most of the trucks apparently ended their journey in Baltimore or continued to other destinations.

"It was just a spontaneous protest," said Lt. Rodney Martin of the Maryland State Police at Pikesville. "They got together over their CB radios early this afternoon and then things grew rapidly. it's kind of a wildcat action, without the support of any organization."

Nevertheless, the convoy had its own coordination. At times the truckers drove well below the speed limit, filling every lane of traffic in the direction they were headed. Late last night traffic was tied up for about five miles on the Capital Beltway from Rte. 95 through Prince George's County as the trucks crept along four abreast.

Their common gripe seemed to be fuel prices.

"We're going broke with the way prices are going up," said trucker Butch Binkarousky as his rig was stopped at the Baltimore Harbor Tunnel.

"Most people don't realize that the independent truck driver carries 80 percent of this country's food," said another driver. "We've got to meet our expenses to operate."

Between 5 and 8 p.m., Maryland State Police barricaded exits to Baltimore from I-95 to prevent truckers from entering the city. State police prevented other motorists from using I-95 for a five-mile stretch through Baltimore.

The truckers' blockade of the harbor tunnel appeared to be in protest of the police barricades. After most rush hour traffic had dispersed, police allowed the truckers to use exits to Baltimore.

But the truckers at first refused to budge and began arguing with tunnel police about playing the toll, complaining that they had been forced to travel through the tunnel instead of using the Baltimore Beltway.

At 8:30, the truckers decided to pay and began moving through the tunnel.