An estimated 650 state and city policemen dispersed a crowd of 500 demonstrators who had occupied the Square for almost two hours last night.

The crowd-largely high school and non-Harvard students-had split off from the Soldiers' Field rally earlier in the evening and had marched to Shannon Hall, headquarters of Harvard ROTC, and the Center for International Affairs (CFIA) before reaching the Square.

The group had intended to occupy or burn down Shannon Hall, but Harvard policemen and students deterred the disorganized crowd from doing more than trashing.

There was also trashing at the CFIA and on Mass Ave., but it never assumed the proportions of the April 15 riot.

Police Clear Square

At 10 p.m. about 150 police marched into the Square from Boylston St. and Brattle St., setting off a minor flurry of trashing, but the police cleared the Square and Mass Ave. within minutes and with a minimum of violence. There were no arrests.

Many medics, legal aids, and marshalls from B.U., Tufts, and Harvard circulated through the crowd in the Square urging them to leave. The students-who were in communication with police authorities-also set up picket lines on Mass Ave. in their efforts to convince bystanders to leave the area.

One-Yard Line

"We were down to the one-yard line," John Buckley, sheriff of Middlesex County, said after the initial police operation. "Our monitors did a great job," he added, referring to the student marshalls.

By midnight only a few police remained in the Square as traffic resumed its normal flow and pedestrians moved along the formerly deserted streets.

University police had locked the gates around the Yard earlier in the evening at the authorization of Archibald Cox '34, Samuel Williston Professor of Law and University spokesman.

Dean May released a statement at 10:15 p.m. last night praising the "good judgment and restraint exercised by Harvard students" throughout the evening and thanking student marshalls for "the courage and skill" they exhibited in calming the demonstrators.

May also noted "the cool judgment and performance" of Cambridge police and municipal authorities in handling the disturbances.

No Connection

In a statement issued late last night, the Harvard Strike Steering Committee said there was "absolutely no organizational connection" between the Harvard Strike and last night's incident.

SDS spokesmen also disclaimed any role in the disturbances. SDS voted at a meeting Thursday night to cancel a planned march to Shannon Hall after yesterday's rally.

Injuries Low

Medics and students reported several cases of severe injuries, including a woman who was trampled by a police charge on Boylston St., but the Cambridge City Hospital and the University Health Services reported ten students and three policemen treated for minor injuries only.

Throughout the evening, the group was leaderless and disorganized-so much so that at one point it lost its way and almost missed Shannon Hall.