Rep. Paul Ryan was ambushed by camera-carrying immigration activists Thursday, the latest Republican to face a tricky confrontation over the issue this month.

The Wisconsin Republican, currently on a bus tour promoting his book The Way Forward: Renewing the American Idea, was challenged by Greisa Martinez, a national organizer with United We Dream, a youth-led organization advocating for immigrants, at a Barnes and Noble in Colorado, according to Roll Call.

Martinez pestered Ryan with questions about congressional inaction on immigration, which caused him to duck into a back room until she was escorted out, according to videos posted by the activists. Two more protesters attempted to talk to him, but were also taken away.

The videotaped ambushes have become a popular tactic for immigration activists seeking to raise the cost of inaction by congressional Republicans. Aside from Ryan, the targets have included other potential 2016 presidential contenders.

• Earlier this week, Sen. Marco Rubio, R-Fla., was confronted by United We Dream members during a fundraiser in Anderson, S.C., angry about his stance on deportation. Rubio voted for a bipartisan Senate immigration reform in 2013 which has stalled in the House.

• Earlier this month, Rep. Steve King, R-Iowa, and Sen. Rand Paul, R-Ky. and were ambushed by two young activists during a fundraising event in Okoboji, Iowa. King is an outspoken opponent of immigration reform. Paul supports the idea, although he voted against the Senate bill.

A February poll by Gallup showed that Americans considered it equally important for the government to secure the borders as well as resolve the status of the roughly 11 million illegal immigrants in the U.S. already.