Mayor Mitch Landrieu speaks next to Cedric Grant, former Executive Director of Sewerage and Water Board, during a press conference about the rebuilding of St. Bernard Avenue near Robert E. Lee Blvd. on Dec. 21, 2016.

WASHINGTON — New Orleans Mayor Mitch Landrieu met with top officials at the federal Department of Homeland Security on Wednesday, lobbying them over a federal inspector general's report that threatens the city's $2 billion global settlement to repair infrastructure damage from Hurricane Katrina.

Landrieu, who's also in the nation's capital on business as president of the U.S. Conference of Mayors, met with Acting Secretary Elaine Duke and other top brass at Homeland Security, the parent agency of the Federal Emergency Management Agency.

Atop the agenda was Landrieu's urgent request to reject the central recommendation in an inspector general's report released in July that recommended FEMA take back the entire $2 billion lump-sum payment to the city for destruction wrought by Katrina to roads and underground pipes.

The inspector general questioned whether all the damage considered in the settlement was actually caused by the devastating 2005 hurricane, pointing to evidence that the city's infrastructure was already aging, decrepit and in poor repair before levee failures sent floodwaters pouring over most of the city.

FEMA officials disagreed with that assessment, arguing that it used technical experts to come to the conclusions that underpin the payment. And city officials have noted that the law governing disaster assistance does not require detailed documentation of the pre-disaster state of the system.

About $400 million to $500 million of the money has already been spent on repairs, said Zach Butterworth, federal affairs director for the city. Much of that money went to fix things like destroyed street lights and signs, infrastructure damage unquestionably caused by the storm.

Butterworth said the city has met with members of Congress and now hopes to convince new leadership at Homeland Security — Gen. John Kelly, the former secretary, is now the White House chief of staff — that the settlement funding is crucial to New Orleans' future.

FEMA is currently formalizing its objections to the inspector general's report, Butterworth said Tuesday, ahead of the meetings. Though the agency has indicated it disagrees with the findings, Butterworth said the amount of money at stake makes the report an alarming and urgent issue for the city.

The $2 billion settlement represents much of the city's cash on hand as it launches work on a huge backlog in street repairs estimated at $9 billion.

Follow Bryn Stole on Twitter, @BrynStole.