BEIRUT -- Lebanese security forces dragged a number of activists out of the Environment Ministry in downtown Beirut, where they were staging an hours-long sit-in on Tuesday demanding the minister's resignation over a trash crisis that has ignited mass protests.

At least one activist, Lucien Bourjeily, was injured and seen being taken away by paramedics.

The group of about 30 protesters from the movement known as "You Stink" marched into the ministry earlier in the day, pushing through security guards at the entrance of the building.

They sat cross-legged on the floor, clapping and shouting slogans against the minister, Mohammed Machnouk, who was holed up in a nearby office.

"Out, out, out!" they shouted.

Angry protests over the government's failure to deal with the garbage crisis have evolved into the most serious anti-government demonstrations in Lebanon in years. The protesters seek to challenge an entire political class that has dominated Lebanon since its civil war ended in 1990.

The protests have attracted supporters from across Lebanon's political and religious divides, reflecting the growing frustration with an aging and corrupt political class that has failed to provide basic services.

Dozens of protesters gathered outside the Environment Ministry later to support their colleagues inside. Riot police kept the protesters from going inside to join the others.

Overcome by heat, a power outage and lack of water, a couple of protesters collapsed inside the building.

Bourjeily told The Associated Press earlier from inside the building that the activists would not leave until the minister resigned. He said the group had decided to stage the sit-in "because someone should be held accountable."

He was among those forcefully dragged out by police later. The state-run National News Agency reported that he had a broken shoulder.

Following a huge protest in downtown Beirut on Saturday, protesters issued several demands including the minister's resignation, threatening to escalate action if he does not.

The minister has refused, resigning only from a government committee assigned to resolve the trash crisis. Garbage has been piling up for weeks since the government closed the city's main landfill without finding a replacement.

"Instead of resigning from the ministry he resigned from his responsibility to deal with the garbage issue," said Bourjeily. "We are left with no choice, we want to make ourselves heard."

So far the only response to the growing protest movement has been a promise by the parliament speaker for high-level talks between Lebanon's politicians in the coming days.

Speaker Nabih Berri announced Tuesday that the first dialogue session will be held Sept. 9. His call for dialogue has been backed by the country's main political leaders, but it was unclear how such talks would help break the deadlock. Protesters called it a farce.

Authorities meanwhile erected a tall metal fence on Tuesday around the prime minister's office and government headquarters in anticipation of more protests. Anti-government protests turned violent last week after a few of the protesters repeatedly tried to remove the barbed wire protecting the building.

The government put up a concrete barrier following those protests, which protesters were quick to brand a "wall of shame." That wall was removed less than 24 hours later upon orders from the prime minister.