HARRISBURG - The union representing state troopers said Monday that it had no confidence in Gov. Wolf's choice to lead the Pennsylvania State Police, ramping up the pressure on the governor to withdraw the nomination.

The Pennsylvania State Troopers Association had stayed neutral on Wolf's embattled pick to run the agency. But following the latest flap involving acting Commissioner Marcus Brown - his being captured on video removing road signs that were critical of him - the union's board cast a vote of no confidence, and asked Wolf to recall the nomination.

"The actions and circumstances surrounding Mr. Brown have garnered embarrassing national media attention," Joseph R. Kovel, the union's president, wrote in a letter to Wolf on Monday. "In turn, it has become an embarrassment to your office, our department, and all rank-and-file troopers."

Jeff Sheridan, Wolf's spokesman, said Monday that Wolf chose Brown, who held a similar post in Maryland, because of his many years of experience in law enforcement. He also noted that Brown had apologized for his actions.

Sheridan added: "As the governor said earlier today, he is monitoring the entire situation closely." Speaking to reporters, Wolf reiterated that he was standing by Brown.

On Friday, top Republicans in the Senate also asked Wolf to rescind Brown's nomination, saying there were too many questions involving the career law enforcement officer. Wolf declined.

The GOP-controlled Senate has the power to confirm Brown. A confirmation hearing has not yet been scheduled but is expected this spring.

Senate Majority Leader Jake Corman (R., Centre) on Monday said the latest controversy involving Brown showed he may not have the political backbone to deal with the stresses of the job.

"In your public life, you have negative issues come up," he said. "But that is what you enter into when you enter public life. You've got to stand up and take that."

Last week, Brown was captured on video removing two signs from the side of a road near his home in a Harrisburg suburb. It was not immediately clear whether they were on public land.

The signs criticized Brown for his decision to don the state police's gray uniform even though he did not graduate from the State Police Academy - a move that has upset career troopers. Brown said he removed the signs because they were near his home and could be seen by his children.

The local police chief launched an investigation, saying Brown could be charged with a misdemeanor theft crime.

Brown later apologized for his actions. Wolf has said did the right thing by apologizing.

"For the top cop, that's just not good enough," Corman said.