The U.S. Labor Department late Monday urged a federal appeals court to largely uphold Obama-era regulations that confronted and sought to curtail conflicts of interest in the retirement-investment market.

The government's brief in the U.S. Court of Appeals for the Fifth Circuit, the first filing from Labor Secretary Alexander Acosta that addressed the so-called "fiduciary rule," comes as federal officials move simultaneously to revise provisions of the regulations and perhaps further delay implementation past the Jan. 1, 2018 effective date.

Obama administration officials hailed the Labor Department's fiduciary rule, which was six years in the making, as "a historic step to protect the savings of America's workers." The regulations broadened the scope of "fiduciary" responsibilities, putting a new emphasis on the best interest of retirement-advice clients over profits. President Donald Trump in February urged labor regulators to reassess the rule.