WASHINGTON (Reuters) - The Trump administration defended the Federal Communications Commission repeal of landmark open internet rules known as net neutrality, urging a federal appeals court to reject a challenge.

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In a 167-page court filing late on Thursday, the Justice Department and FCC urged the court to reject the suit filed by 22 states, the District of Columbia, Mozilla Corp, Vimeo Inc, public interest groups and local governments.

The Justice Department said the suit offers “no substantial reason to second-guess the commission’s decision to eliminate rules that the agency has determined are both unlawful and unwise.”

The FCC voted 3-2 in December along party lines to reverse rules adopted in 2015 that barred internet service providers from blocking or throttling traffic, or offering paid fast lanes, also known as paid prioritization.

Under the net neutrality rules, internet service providers have to treat all data fairly. Supporters of the rules fear providers could otherwise censor some data or raise costs for connectivity for some users.

The FCC also sought to pre-empt states from setting their own rules governing internet access.

A group of Democratic members of Congress, including Representative Nancy Pelosi and Senator Chuck Schumer, major cities, including New York, Boston and Chicago, back the states’ challenge, while trade groups representing major cable and mobile phone companies support the FCC action.

The Justice Department earlier this month filed suit to block California’s state net neutrality law from taking effect in January.

The net neutrality repeal was a win for providers like Comcast Corp, AT&T Inc and Verizon Communications Inc, but was opposed by internet companies like Facebook Inc, Amazon.com Inc and Alphabet Inc, which say the repeal could lead to higher costs.

The U.S. Senate voted in May to reinstate the net neutrality rules, but the measure is unlikely to be approved by the House of Representatives.

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

The Justice Department said the transparency rules “discourage broadband providers from engaging in harmful practices by reducing their incentives and ability to do so” and suggested it would allow “the market to prompt broadband providers to take corrective measures.”

Supporters of net neutrality argue that in some places, consumers do not have a choice among high-speed broadband providers.

The Justice Department brief also argues that banning paid prioritization may be “economically inefficient,” while suggesting that blocking or throttling will not happen because providers do not have an “economic incentive” to do so.

The U.S. Court of Appeals for the District of Columbia will hold oral arguments on the case on Feb. 1.