WASHINGTON (AP) — Advocates for people with mental illness and HIV are joining other consumer groups in a lawsuit to block one of the Trump administration's main approaches for making low-cost health insurance more widely available.

The case filed Friday in U.S. District Court in Washington, D.C., takes aim at so-called short-term plans that don't have to cover people's pre-existing medical conditions, or provide standard benefits like prescription drugs. The administration recently adopted regulations to encourage the spread of such plans, featuring premiums about one-third the cost of comprehensive insurance.

Among their arguments, the groups say that those regulations violate the Obama-era Affordable Care Act.

The administration says short-term plans may not be right for everyone, but they could be an important option for some consumers who can't afford "Obamacare."