WASHINGTON — Sign-ups for health insurance plans through the Affordable Care Act continued to surge this month amid anxiety about the future of the law under President-elect Donald Trump, according to the U.S. Department of Health and Human Services.

The flood of people signing up since enrollment began Nov. 1 surpassed 1 million on Saturday, outpacing enrollment from last year.

The sign-ups, which accelerated after last week’s election, highlight anew the high stakes in the coming battle over repealing ObamaCare, which Trump and his congressional allies have pledged to do early next year.

More than 300,000 people selected plans Nov. 9 to 11, the health agency reported. That post-election period also coincided with stepped-up outreach efforts.

There were 53,000 more sign-ups during the first 12 days of open enrollment this year than last, according to the health agency.

The increase comes amid rising uncertainty about the fate of the insurance system set up by the 2010 health law.

The system, which relies on insurance marketplaces and expanded access to Medicaid, has recorded historic gains over the last three years, as some 20 million previously uninsured Americans have gained health insurance since 2013. In the same period, the nation’s uninsured rate dropped to the lowest level ever recorded.

Trump and congressional Republicans have said they will replace the system in a way that ensures people don’t lose coverage. But the GOP has not advanced any alternatives.