An attempt to break into University President Lawrence H. Summers’ Cambridge mansion was thwarted Saturday afternoon when the resident caretaker saw the intruder and notified Harvard police.

Daniel Snyder, 24, was arrested for trespassing on the University-owned residence and attempting to force open a door to the basement of Summers’ estate. He is being charged with trespassing and attempting to commit a crime, said Harvard University Police Department spokesperson Peggy McNamara, who did not know last night whether Snyder had been released from police custody.

After the caretaker saw Snyder walk across the Elmwood Avenue estate’s lawn and activate a motion detector, he pushed a panic button, notifying Harvard police at 3:42 p.m., McNamara said.

When they arrived, officers found Snyder attempting to push open a bulkhead door leading into the basement, McNamara said.

Summers, whose home earlier this year suffered $25,000 in damage following an accidental microwave fire, said he was at home when Snyder allegedly attempted to enter, but that he never saw the intruder.

There was no damage to the house, he added yesterday night after escaping a mob of Summer School students seeking autographs, photographs or a word with the president. Summers had just delivered a Science Center speech opening the summer session.

Snyder’s 375 Mt. Auburn St. home is about a block away from Summers’ 33 Elmwood Ave. home.

—STEPHEN M. MARKS and ELISABETH S. THEODORE