WASHINGTON (Reuters) - The Obama administration on Friday said it would stop enrolling new beneficiaries in a special $5 billion insurance program for people with pre-existing medical conditions, because of rising costs and limited funding.

The news comes a day after a top U.S. healthcare official told lawmakers on Capitol Hill that the administration is grappling with financial difficulties but determined to keep the Pre-Existing Condition Insurance Plan (PCIP) operating in 23 states and the District of Columbia through 2013.

PCIP was established in 2010 under President Barack Obama's healthcare reform law to provide coverage for sick people unable to find it in the private insurance market. The program is designed as a bridge to January 1, 2014, when legal restrictions barring discrimination over medical conditions come into force.

The U.S. Department of Health and Human Services issued a notice on Friday saying it would suspend new enrollments beginning on Saturday to "help ensure that funds are available through 2013 to continuously cover people currently enrolled in PCIP."