Federal Emergency Management Agency head Brock Long hit out at criticism of the administration's handling of the crisis in Puerto Rico following Hurricane Maria, saying it was the most "challenging" relief effort in U.S. history.

"I think the secretary's words are being taken out of context," Long said in reference to the backlash Acting Homeland Security Secretary Elaine Duke received for calling the recovery "a good news story." "The bottom line is that this is the most logistically challenging event the United States has ever seen and we have been moving and pushing as fast as the situation allows."

The FEMA administration confirmed 16 people had died on Puerto Rico, which was lashed by Hurricanes Irma and Maria in September.

Long added while "every day we have progress," speaking of the 13,000 staff and volunteers working to help the U.S. island territory, "every day we have some setback."

For example, 11 major highways had been re-opened so resources can be delivered to impacted residents, but 3,200 additional roadway problems have also been reported to FEMA, he said.

The main difference between the agency's response to Hurricane Harvey and now is infrastructure was "fragile in Puerto Rico after two severe weather events," he continued.

"The problem and the frustration is the way information is being misrepresented across the board," he said, citing misreports about fewer planes carrying aid arriving at the airport serving the Puerto Rican capital of San Juan. "I don't have time for that. What we have time for is being laser-focused to help Puerto Ricans."

Long said one of the responses' strengths was its access to relief commodities and its communication between agencies and the various levels of government, which will be important as they try to restore power on the island.

But he added he didn't have patience for politics, as tensions rise between President Trump and San Juan Mayor Carmen Yulin Cruz, saying the recovery will also depend on the private sector.

"If mayors decide not to be a part of that, then response is fragmented," Long said. "We can choose to look at what the mayor spouts off or what other people spout off but we can also choose to see what is actually being done, and that is what I would ask."