SAN DIEGO, California (AP) — A federal judge on Tuesday halted major fee increases for citizenship and other immigration benefits three days before they were to take effect, saying the last two chiefs of the Homeland Security Department were likely appointed illegally.

US District Judge Jeffrey White found Kevin McAleenan improperly leapfrogged to acting secretary when Kirstjen Nielsen resigned in April 2019. The judge said McAleenan, as Customs and Border Protection commissioner, was seventh in line to assume the acting role under rules of succession at the time.

Chad Wolf, who became acting secretary after McAleenan resigned in November, was also promoted out of order from his position as under secretary for strategy, policy and plans, said White, ruling in Oakland, California.

White, who was appointed by President George W Bush, also blocked the fee hikes on grounds that the Trump administration likely failed to adequately consider the impact of the changes as required under federal rule-making, including their effect on low-income applicants.

The Homeland Security and Justice departments did not immediately respond to requests for comment Tuesday night. US Citizenship and Immigration Services, the agency with Homeland Security that awards citizenship, green cards and temporary work permits, said it was reviewing the decision.

Homeland Security strongly disagreed with a finding in August by the Government Accountability Office, a congressional investigative agency, that McAleenan, Wolf and Ken Cuccinelli, the department’s second-highest ranking official, were appointed illegally.

President Donald Trump nominated Wolf to be secretary September 10 — exactly 17 months after Nielsen stepped down as the last Senate-confirmed leader of the department. The Senate has not yet acted on Wolf’s appointment.

Fees were set to increase by an average of 20 per cent on Friday.

Changes were to include a first-ever fee for applying for asylum of US$50. Asylum-seekers would also have to pay US$550 if they sought work authorisation and US$30 for collecting biometrics.

The fee to become a naturalised citizen was set to jump to US$1,170 from US$640. Fee waivers were to be largely eliminated for people who cannot afford to apply.

Eight advocacy groups sued the administration in August after Homeland Security published a final version of the fee hikes, incorporating public feedback. McAleenan initially proposed the hikes in November in one of his last acts as acting secretary.

“The injunction will ensure that millions of low income immigrants, applicants for naturalisation, asylum seekers, survivors of domestic violence and survivors of human trafficking will be able to affordably apply for the immigration benefits they are eligible for,” said Melissa Rodgers, director of programs for the Immigrant Legal Resource Center, one of the plaintiffs.

The Migration Policy Institute recently catalogued more than 400 actions under Trump to reshape immigration policy, including border enforcement, asylum eligibility and vetting for visas. Many are being challenged in court.

Lawyers suing the administration are increasingly questioning the legitimacy of actions taken by McAleenan, Wolf and Cuccinelli but it is unclear how often those arguments will prevail. A federal judge in Maryland said this month that the appointments of McAleenan and Wolf were invalid because they didn’t follow the order of succession, ruling in a case over a new one-year waiting period for asylum-seekers to apply for work permits.