In a major setback to Harvard's relations with Cambridge, city councillors last night accused the University of abandoning its long-time host city as it courts new developments in Boston.

The University had planned to announce last week a $100,000 gift for a summer school program in Cambridge. But just days before that announcement had been scheduled, the University unveiled a much larger donation--$5 million over five years--to fund afterschool programs in Boston.

Councillors said they felt slighted by the University's decisions. They said they had heard nothing of the Boston initiative before it was announced and had been taken by surprise by newspaper articles last week describing the richer gift.

Saying that relations with Harvard had deteriorated to a new low, councillors chastised University officials for the monetary disparity and blasted them for leaving Cambridge's elected officials out of the loop.

"I have never seen the council so shocked and dismayed at the actions of a university as I have seen tonight," said Councillor Kathleen L. Born.

At its regularly scheduled meeting last night, the council unanimously passed a resolution proposed by Mayor Anthony D. Galluccio urging the University to match its $5 million Boston gift in Cambridge.

Gallucio's "call to action" expressed "extreme disappointment" with the unequal allotment of money and asked residents affiliated with Harvard to pressure the University to match its Boston gift in Cambridge.

Councillors sounded aggressive notes last night, saying their unanimity in support of Galluccio's resolution showed the council had closed ranks against the University.