The Obama administration is continuing to resist efforts by a top House Republican to gain access to the internal deliberations of federal scientists who authored a groundbreaking global warming study the lawmaker is investigating.

In response to a threat from House Science Committee Chairman Lamar Smith (R-Tex.) to subpoena Commerce Secretary Penny Pritzker, the head of the National Oceanic and Atmospheric Administration told Smith in a letter Friday that her staff will not be influenced by political interference.

“I have not or will not allow anyone to manipulate the science or coerce the scientists who work for me,” Administrator Kathryn Sullivan wrote.

“If the committee doubts the integrity of the study,” Sullivan wrote, “it has the tools it needs to commission a competing scientific assessment.”

Sullivan was responding to Smith’s claim last week that the climate study, published in June in the peer-reviewed journal Science, was “rushed to publication” over the objections of some NOAA scientists.

Smith, a prominent congressional climate-change skeptic, has for weeks demanded internal documents and e-mails from NOAA he says will prove that the scientists manipulated global temperature data to advance President Obama’s climate agenda. Sullivan has refused to turn them over. The lawmaker then appealed to Pritzker, whose agency includes NOAA, and threatened to subpoena her.

The study refuted claims that global warming had “paused” or slowed over the past decade, undercutting a popular argument used by skeptics like Smith who disagree with the scientific consensus that man-made pollution is behind global warming.

“Dr. Karl’s study reflects the essence of the scientific process, which involves continually refining conclusions as new data and information is discovered,” Sullivan wrote, referring to Thomas Karl, who led the NOAA team.

She said her agency “is willing to continue to work with the Committee to accommodate its oversight needs,” but it was not immediately clear what she would turn over short of the internal deliberations and communications she has so far refused to provide.

Sullivan also clarified the timeline of the study, telling the chairman that the data her team relied on has been publicly available since July 2014.

The Science paper was submitted in December 2014 and published in June.

Sullivan sought to refute Smith’s claims of political interference, telling him, “Mr. Chairman, let me assure you that I am not engaged in or associated with any ‘politically correct agenda.'”