U.S. intelligence is urging the Obama administration to check its new health care computer network for malicious software after learning that developers linked to the Belarusian government helped produce the website, raising fresh concerns that private data posted by millions of Americans could be compromised.

The intelligence agencies notified the Department of Health and Human Services, the agency in charge of the HealthCare.gov network, about their concerns last week. Specifically, officials warned that programmers in Belarus, a former Soviet republic closely allied with Russia, were suspected of inserting malicious code that could be used for cyberattacks, said U.S. officials familiar with concerns.

The software on the website links the millions of Americans who signed up for Obamacare to the government and more than 300 medical institutions and health care providers.

“The U.S. Affordable Care Act software was written in part in Belarus by software developers under state control, and that makes the software a potential target for cyberattacks,” one official explained, speaking only on the condition of anonymity.

Cybersecurity officials said the concerns are compounded by an Internet data “hijacking” incident last year involving Belarusian state-controlled networks. The monthlong diversion covertly rerouted massive amounts of U.S. Internet traffic to Belarus — a repressive dictatorship country bordering Russia, Poland and Ukraine.