A senior White House official said Monday that regulations to toughen oversight of oil-and-gas “fracking” on federal lands are on track despite a two-month extension of the public comment period announced last week.

Heather Zichal, the top White House energy aide, told reporters that she expects the Interior Department rules regulating hydraulic fracturing, dubbed fracking, to be completed by year’s end.

An Interior department spokesman offered the same forecast Friday. But the comments from a senior White House official could help ease jitters among environmentalists, who fear the extension of the comment period, until mid-September, on the draft rules could set back the measure.