NEW YORK — Under pressure over his handling of abuse allegations against a top aide, White House chief of staff John Kelly on Friday ordered sweeping changes in how the White House clears staff members to gain access to classified information, acknowledging that the administration “must do better” in how it handles security clearances.

Kelly issued a five-page memo that acknowledged White House mistakes but also put the onus on the FBI and the Justice Department to provide more timely updates on background investigations, asking that any significant derogatory information about staff members be quickly flagged to the White House counsel’s office.

The issue has been in the spotlight for more than a week after it was revealed that former staff secretary Rob Porter had an interim security clearance that allowed him access to classified material despite allegations of domestic violence by his two ex-wives.

“Now is the time to take a hard look at the way the White House processes clearance requests,” Kelly wrote in the memo. “We should – and in the future, must – do better.”

The memo said the FBI and Justice Department also had offered increased cooperation.