TOKYO, Oct. 21 (NYT) — Bands of students virtually paralyzed Tokyo today as they roamed the streets hurling gasoline bombs and smashing windows in observance of International Anti-War Day.

Similar violence broke out in nearly 100 other Japanese cities.

Trade unionists, Communists, and left-wing political groups assembled at nearly 800 rallies in different parts of the country to demand the abrogation of the Japan-United States security treaty and the immediate return of Okinawa to Japan.

Some 70,000 riot police — 25,000 of them in Tokyo — attempted to control the demonstrations and by midevening nearly 1,100 students had been arrested in Toyko alone.

In contrast to past demonstrations, when helmeted students bearing brilliantly-colored banners and armed with staves marched in columns against pre-announced targets and engaged police in mass battles, the students today used hit-and-run “guerrilla” tactics. Small or medium-sized bands of students swooped down on their target, hurled Molotov cocktails and tried to escape before the police could arrive.