WASHINGTON — A group of 22 state attorneys general and the District of Columbia late Monday asked a US appeals court to reinstate the Obama administration’s 2015 landmark net neutrality rules and reject the Trump administration’s efforts to preempt states from imposing their own rules guaranteeing an open internet.

The states, led by New York Attorney General Barbara Underwood, filed a lawsuit in January after the Federal Communications Commission (FCC) voted in December along party lines to reverse rules that barred internet service providers from blocking or throttling traffic or offering paid fast lanes, also known as paid prioritization.

Several internet companies filed a separate legal challenge Monday to overturn the FCC ruling, including Mozilla Corp., Vimeo Inc., Etsy Inc. and numerous media and technology advocacy groups.

The FCC handed sweeping new powers to internet providers to recast how Americans use the internet — as long as they disclose any changes. The new rules took effect in early June but major providers have made no changes in internet access.

The states argue the FCC reversal will harm consumers.

The states also suggested the FCC failed to identify any “valid authority” for preempting state and local laws that would protect net neutrality.

Governors in six states have signed executive orders on net neutrality, while three states have enacted net neutrality legislation.

FCC Chairman Ajit Pai has repeatedly said he believes the rules will be upheld and will encourage additional investment by providers. A spokesman for Pai did not immediately comment late Monday.

The revised rules were a win for internet service providers, like Comcast Corp., AT&T Inc. and Verizon Communications Inc., whose practices faced significant government oversight and FCC investigations under the 2015 order, but the rules were opposed by internet firms like Facebook Inc., Amazon.com Inc. and Alphabet Inc.

The FCC failed to offer a “meaningful defense of its decision to uncritically accept industry promises that are untethered to any enforcement mechanism,” the states said.

The US Senate voted in May to keep the Obama-era internet rules, but the measure is unlikely to be approved by the House of Representatives or the White House.

The state attorneys general suing represent states with 165 million people — more than half the United States population — and include California, Illinois, New Jersey, North Carolina, Pennsylvania and Virginia.

The states argue the FCC action could harm public safety, citing electrical grids as an example. They argue that “the absence of open internet rules jeopardizes the ability to reduce load in times of extreme energy grid stress. Consequently, the order threatens the reliability of the electric grid.”