Two activists were deported from Qatar on Thursday after calling for more leadership on tackling climate change from the Gulf state, which is hosting UN talks in Doha, their campaign group said.
Libyan Raied Gheblawi, 22, and Algerian Mohamed Anis Amirouche, 19, held up a banner in the conference hall's central meeting point reading "Qatar, why host not lead?"
"Both were stripped of their badges and asked to leave the hall by security guards. They were told to return to their hotels and be at the airport no later than 12 am," said a spokesman for IndyAct, a regional advocacy group on climate change policy of which both deportees are members.
"They were trying to draw attention for the need for Qatar to take a real leadership role in these last 48 hours of the negotiations. They did nothing but hold up a banner."
The Qatari government was not reachable for comment.
Delegates from 200 nations have gathered in Qatar for the November 26-December 7 summit to try to agree an extension to the UN Kyoto Protocol, a treaty that obliges about 35 developed nations to cut their greenhouse gas emissions.
Qatar has come in for particular criticism as it has so far failed to set clear targets for reducing its own emissions.
However the tiny Gulf state argues that its liquefied natural gas exports mean it is helping other nations move away from using more polluting coal.
It has also promised to raise the proportion of electricity generated via solar power to 16 percent by 2018, and on Wednesday said it would establish a climate change research centre with Germany's Potsdam Institute.
Campaigners say they expect more from one of the world's richest counties with the highest emissions level per-capita.
Finance is a huge stumbling block at the meeting. Many developed countries, facing economic difficulties at home, are reluctant to set new aid targets to help poorer nations curb their fast-rising emissions and cope with floods, droughts and rising seas.