Sections of the Patriot Act expired at midnight Monday morning after the Senate failed to pass a measure during Sunday's session that would extend them.

One of the affected provisions that expired Monday was the Patriot Act Section 215 -- which allowed for the National Security Agency's bulk collection and storage of domestic phone metadata, a practice revealed by former NSA contractor Edward Snowden.

U.S. Sen. Rand Paul spearheaded opposition in the Senate on Sunday against renewal of the expiring Patriot Act provisions. 

The Senate did advance for consideration the USA Freedom Act, a compromise government surveillance reform bill supported by the White House that would effectively end the NSA's bulk collection of domestic phone records. 

However, the Senate adjourned at about 9:45 p.m. after it was clear that the debate period over the measure would not be completed before the midnight deadline.

A Senate vote on a compromise USA Freedom Act measure could happen as early as Tuesday.