WASHINGTON – The new head of the U.S. Secret Service acknowledged Tuesday that days passed before he was told about the latest allegations of misconduct at the agency, but pleaded for patience from skeptical lawmakers calling for stronger action to restore confidence in the protective service after a string of scandals.

In testimony before a House panel, agency Director Joseph Clancy said it was unacceptable that it took an anonymous whistleblower for him to learn that two senior agents, allegedly under the influence of alcohol, hit a barricade with a government vehicle March 4 and disrupted an investigation on the White House grounds.

But he also sought to cast the episode as less egregious than reports have suggested, saying the agents nudged the barricade on purpose with their vehicle to move it out of the way, for example, rather than running into it. He said he was waiting to discipline the men to avoid impeding an outside probe.

"This is my first test," he said. "I'm frustrated that we can't act until we get all the facts, but I just don't want to act improperly too soon."

Still, members of both parties questioned whether Clancy was the right man for the job, asking why he could not act more quickly.

"We've got to have some changes. And you have to be the one to make those changes. And I don't sense at the moment that you have the determination to make that happen," said House Appropriations Committee Chairman Hal Rogers, R-Ky.

Clancy, a 27-year veteran of the Secret Service, was named last month as the permanent head of the agency. His appearance before a House Appropriations subcommittee was the first of two on Capitol Hill this week on his agency's budget request.

Lawmakers, though, appeared more interested in demanding answers about a string of incidents involving agency personnel. The chairman and the top Democrat on the House Oversight Committee have also called Clancy in for a private discussion of the incident, which they have said "exhibits a clear lack of judgment in a potentially dangerous situation."

As the former head of President Obama's security detail, Clancy had earned the president's trust ahead of his new critical assignment. Obama appointed him against the advice of an independent panel that recommended last fall that only an outsider could deliver needed change in the culture of the agency after a series of scandals culminated in a major breach in September, when a Texas man hopped a fence and evaded other layers of security to storm into the White House.

The White House has said it is standing behind Clancy.