Washington (CNN) The White House's Office of Management and Budget is planning for a lapse in funding as of Thursday evening in preparation for a possible shutdown, an OMB official told CNN.

The official said OMB had contacted government agencies seven days ago, telling them to be prepared for the possibility of government shutdown, and on Thursday OMB emailed the agencies, advising them to get their plans together and to update staff on who will be affected and what the plan would be.

Just hours ahead of the midnight deadline to keep the government open, Republican Sen. Rand Paul of Kentucky held up a key vote on a spending agreement backed by leaders of both parties in the Senate as well as President Donald Trump.

The official said it is up to individual agencies how they would handle a shutdown, but even those affected by a potential lapse in appropriations would be able to come into work for up to four hours to conduct an orderly shutdown.

The official added that all of the agencies' shutdown plans are listed on OMB's website, and that just as during January's brief government stoppage, many workers in safety and security are considered exempt from a shutdown.

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