Information from 75,000 people who use the federal government's Obamacare website was hacked earlier this week, the Centers for Medicare and Medicaid Services reported Friday.

Staff at the agency, known as CMS, said in a statement that they noticed "anomalous activity" in a part of the site that allows agents and brokers to connect people with health insurance. The agency did not say who was responsible for the hack, but said it had followed protocol by notifying federal law enforcement officials.

The number of people affected represents a small fraction of the roughly 9 million people who enroll in the system, but CMS called the breach "unacceptable."

“Our number one priority is the safety and security of the Americans we serve," CMS Administrator Seema Verma said in a statement. "We will continue to work around the clock to help those potentially impacted and ensure the protection of consumer information."

The site is still accessible and open enrollment, the time during which people can buy plans or switch policies, is still scheduled to start on time Nov. 1. The agency is notifying people who were affected.

When people sign up for coverage they include information about their income and identities, as well as where they live and what their smoking status is.

CMS noticed strange activity on the site, specifically the feature known as Direct Enrollment, Oct. 13 and declared a "breach" Oct. 16 and deactivated accounts associated with agents and brokers. The agency expects to re-econnect the brokers and agents within seven days.