A GOP energy press conference turned into a shouting match between lawmakers and protesters Monday as nearly 200 environmental advocates crashed the event and drowned out most of the Republican pro-drilling rhetoric.

Armed with signs and dressed as Arctic birds, the activists booed and erupted into anti-oil drilling chants throughout the press event, which GOP leaders held to mark the culmination of their monthlong protest of Democrats’ refusal to allow a floor vote on offshore drilling.

House Minority Leader John Boehner (R-Ohio) said Republicans are “going to force a vote” on their energy package, which calls for new Arctic and offshore drilling.

Asked if GOP leaders are willing to shut down the government if Democratic leaders refuse to lift the ban on offshore drilling, Boehner said Republicans are going to “do everything we can” to get an up-or-down vote.

About 160 people from environmental groups around the country are in Washington, D.C., this week to lobby lawmakers about protecting wilderness and Arctic areas. This is in addition to another 40 based in Washington who are planning to play an active role in the energy debate over the next few weeks.

Advocates declined to say whether they could support a Democratic energy bill with limited offshore drilling, something Speaker Nancy Pelosi (D-Calif.) has said is coming. Most said they wanted to see the bill before weighing in.