By Kathleen Hennessey, Tribune Washington Bureau

ROME — With a March 31 deadline looming, the White House announced Thursday that more than six million people have signed up for health insurance through online marketplaces created by the Affordable Care Act.

That number falls short of the goal of seven million sign-ups that administration officials had hoped to reach before website troubles botched the Oct. 1 rollout of the federal marketplace.

Still, the figure shows the administration has made a strong comeback, which could quiet concerns that the new system would fail to get a large enough pool of consumers to work as planned.

And it assures that, with several more days to go until the deadline, the administration will surpass the six million enrollment estimate released last month by the nonpartisan Congressional Budget Office.

Obama, on a conference call from Italy on his five-day Europe trip, touted the new milestone Thursday to supporters and volunteers. The president asked the group, which the White House said numbered several thousand, to continue their efforts through the final push.

“The president encouraged the navigators and volunteers to redouble their efforts over the next four days and leave no stone unturned in trying to bring affordable health coverage to as many Americans as possible,” the White House said in a statement.

Both state and federal marketplaces have seen a surge of activity ahead of Monday’s deadline. On Wednesday there were more than 1.5 million visits to the federal site, HealthCare.gov, and more than 430,000 calls to call centers, according to the White House. The administration previously announced the site — the marketplace for 36 states — drew 1.2 million visitors Tuesday and 1.1 million Monday.

The hard date for enrolling in Obamacare this year is now a softer deadline. The administration has said that consumers who have started the process of enrolling will be able to get an extension to complete the process after Monday, but has not indicated for how long.

The administration has not released data on how many people have actually paid for the health insurance plans that they have selected.

Unofficial estimates from insurance companies and some state-run marketplaces suggest that as many as 20 percent of consumers have yet to pay their premiums, although some of those may not have been billed yet.

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