National Park Service acting director Mike Reynolds, left, and Interior Secretary Ryan Zinke address Park Service employees at Grand Canyon National Park, Ariz., on Friday. (Felicia Fonseca/AP)

Interior Secretary Ryan Zinke said Friday that he was determined to end a culture of misconduct inside the National Park Service as a new survey found that almost two in five employees experienced harassment or discrimination in the past year.

The long-awaited survey also found that more than one in 10 employees felt sexually harassed on the job. The report confirmed a pattern of widespread misconduct that broke into the open two years ago with a scandal at the Grand Canyon National Park, where investigators found that male employees preyed on female colleagues during long trips down the Colorado River.

The agency's internal watchdog also uncovered similar harassment at multiple parks across the far-flung system, including Yosemite, Yellowstone, Canaveral National Seashore and the De Soto National Memorial.

[As the National Park Service confronts sexual harassment, this dysfunctional park is Exhibit A]

Zinke and top Park Service officials said Friday that they were taking stepped-up measures to root out harassment — including acting swiftly to fire employees involved in misconduct.

"The days of watching things, not saying anything and not taking action are over," Zinke told employees at the Grand Canyon in remarks broadcast to the Park Service's 23,000-person workforce, which is 40 percent female.

Zinke said he fired four "senior leaders" in recent weeks, adding, "The consequence of [these] actions has to be clear."

An Interior Department official said the terminations were of senior executives and other senior officials and that the offenders were guilty of sexual harassment, intimidation and abuses of authority. They worked at various agency bureaus.

[Lawmakers charge Park Service chief oversees culture of harassment]

The Park Service survey comes amid an intensifying national focus on sexual harassment, with allegations against powerful figures such as movie producer Harvey Weinstein spurring new scrutiny in many workplaces.

Grand Canyon Superintendent Chris Lehnertz, whose predecessor was forced out for failing to respond to complaints from victims, said, "If you are at the Grand Canyon and you're a predator, we're going to find a way to terminate your employment with the National Park Service."

Lehnertz said "the nation was appalled" by the Grand Canyon case, adding that it "changed lives, it changed families, it changed careers."

In January 2015, the Interior Department's inspector general released an explosive report that found that for years boatmen in the park had propositioned female employees in the Grand Canyon's river district, groping and bullying them. One employee said that a boatman withheld food from women who refused his sexual advances during a Park Service trip.

Several employees resigned or retired in the fallout, including the former park superintendent, who investigators found had ignored the women's complaints. One of the boatmen accused of misconduct was not fired until last summer, 19 months after the inspector general's report.

[Female Park Service employees say they were groped, propositioned and bullied on Grand Canyon river trips]

Lehnertz blamed the isolated workplaces of most Park Service employees for creating an environment that fosters harassment, saying, "Isolation magnifies the abuse of power."

On Friday, Zinke called on employees to report misconduct to their supervisors, urging them to go up the chain of command if their complaints were ignored. He lamented that the issue was taking a toll on the Park Service, saying: "It's killing our morale."

About half of Park Service employees responded to the survey of workplace conditions, which was conducted from January through March by the Federal Consulting Group and the CFI Group. A separate survey of thousands of seasonal employees who staff the parks in the summer months will be released in the coming weeks, officials said.

The report released Friday found that 38.7 percent of employees said they experienced some harassment or discrimination in the previous 12 months, saying they were targeted because of their age, race, gender, religious beliefs and sexual orientation, among other factors. Fewer than 1 percent said they were sexually assaulted.

Three-quarters of the employees who said they were harassed did not report it. Of those who did file complaints, only about a third said the Park Service acted on their complaints.

Acting Park Service chief Mike Reynolds called the survey results "very sobering." He apologized to "all of the employees at the Grand Canyon who have suffered."

"I am resolute to correct this," he added.

Reynolds laid out steps the agency is taking to combat harassment, including hiring more staff to investigate complaints, improving training and building a robust network of employee support groups. Many of those efforts were initiated by Zinke's predecessor, Sally Jewell.

Complaints about sexual harassment have long dogged the Park Service. The agency set up a task force in the 1990s to gauge the extent of the issue and found widespread problems. But it did little to address these findings, in part because of budget constraints, officials told The Washington Post last year.

The most recent cases led to congressional hearings last year, during which Democratic and Republican lawmakers scolded the Obama administration for letting misconduct fester.

House lawmakers criticized a lack of accountability at the top of the agency, telling former Park Service chief Jonathan Jarvis that he should have moved faster to fire or discipline managers and employees who had harassed their colleagues.