WASHINGTON (AP) — Programmers building the Obama administration's showcase health insurance website say they were pressed for time and grew frustrated over last-minute changes to the system.

Project developers told The Associated Press they were concerned whether the site could be ready in time and complained about what they saw as unrealistic deadlines. They spoke to the AP on condition of anonymity because they feared they would otherwise be fired.

Obama on Monday offered no explanation for the failures except to say that high traffic to the website caused some slowdowns. He said no one was more frustrated than he was, but he stopped short of apologizing for website glitches that are deeply embarrassing for the White House.

Uninsured Americans have until about mid-February to sign up for coverage or face a penalty.