BONN, NOV. 19 -- Who says the Cold War is over? The incursion military strategists feared for 45 years finally happened today, when a Soviet armored personnel carrier eluded allied defenses and rolled into west Berlin.

In the still of night, the tank-like vehicle clattered into the city center and down the main shopping boulevard, eluding police and leaving behind numerous wrecked cars.

The incursion, which a U.S. diplomat said could easily have started a war a year ago, ended after five hours with the revelation that a 20-year-old Soviet soldier from the Ukraine, after a lovers' quarrel, got behind the wheel and let off steam.

Soviet military prosecutor Oleg Filippenko was almost too ashamed for words. Hundreds of his troops in Germany have been deserting in recent weeks, and now this.

His country is terribly sorry for the "unrest that has occurred," the official told the German news agency Deutsche Presse-Agentur. It seems the young soldier had a "fight with his girl friend."

The adventure began at 3 a.m., when the unidentified soldier managed to sneak the personnel carrier out of the Soviet base in Saarmund, near Potsdam and about 16 miles from downtown Berlin. Many of the 380,000 Soviet troops to remain in eastern Germany for four years are based in barracks near Berlin.

German police first saw the hijacked vehicle in Potsdam at about 4 a.m. They tried to stop it, but the grieving soldier steered around roadblocks and speeded up.

Squad cars followed the soldier through the rest of his trip. Police also notified local radio stations, who broadcast a warning for Berliners to clear off the streets.

The soldier made excellent time into the city, cruising along at about 30 miles per hour into west Berlin, along the glittering Kurfuerstendamm, out into the dreary suburbs of eastern Berlin and eventually back to his base.

Soviet soldiers in a variety of vehicles joined the chase and back in Potsdam, a Soviet sergeant jumped onto the front of the vehicle and threw a blanket over the vision slit. The soldier stopped and gave up without a fight.

The lovelorn Ukrainian was in the hands of German police tonight. Until the two Germanys unified last month, Soviet soldiers were under the sole authority of their own military. But the new rules say Soviet soldiers based in the country are subject to German law.

Soviet prosecutor Filippenko said, nevertheless, "This will have consequences."