The Department of Health and Human Services says it is also bringing in technology experts from inside and outside of government to help diagnose the issues. HHS, in a memo released Sunday, said it was also putting in place "tools and processes to aggressively monitor and identify parts of HealthCare.gov where individuals are encountering errors or having difficulty using the site, so we can prioritize and fix them." Obama will be flanked at the Rose Garden event by people the White House says have already enrolled during the first three weeks of sign-ups. Enrollment figures are being closely guarded by the administration, which plans to release the first round of data in mid-November. Officials did say over the weekend that nearly a half million applications have been filed through the federal- and state-run exchanges. Users must file applications before they can enroll, in part to find out whether they are eligible for government subsidies. The White House also says about 19 million people have visited HealthCare.gov since Oct. 1. Administration officials initially blamed a high volume of interest for the frozen screens that many people encountered. Since then, they have also acknowledged problems with software and some elements of the system's design. Despite the widespread problems, the White House has yet to fully explain exactly what went wrong with the online system consumers were supposed to use to sign up for coverage. In an ironic twist, the troubles with the health care rollout were overshadowed by Republican efforts to delay or defund "Obamacare" in exchange for reopening the government during the 16-day shutdown. The bill that eventually reopened the government included no substantive changes to the health care law. With the shutdown over, GOP lawmakers were ramping up their criticism of the health care law's troubles. "Obamacare costs too much and it's not working the way they promised," Senate Minority Leader Mitch McConnell, R-Ky., said. And Brendan Buck, a spokesman for House Speaker John Boehner, said of Obama's Monday event: "A speech doesn't solve the problem." Some Republicans are also calling for the resignation of HHS Secretary Kathleen Sebelius. The White House says it has complete confidence in her. House Republicans have scheduled a hearing next week to look into the rollout problems. Copyright 2013 The Associated Press.