NEW YORK — A standoff between striking school bus drivers and aides looking for job protections and a city administration that says they just can't have it has the potential to go on for some time, observers said, as parents scrambled for a second day to figure out alternatives for tens of thousands of students who need to get to school.

Union head Michael Cordiello said the drivers will strike until Mayor Michael Bloomberg and the city agree to put a job security clause back into their contract.

"I came to urge the mayor to resolve this strike," Cordiello, president of Local 1181 of the Amalgamated Transit Union, said on Tuesday. "It is within his power to do so."