KATOWICE, Poland (AP) " Campaign group Climate Action Network says one of its employees has been allowed to enter Poland after earlier being stopped by border guards citing unspecified security threats.

The group, an alliance of hundreds of organizations from around the world, said Polish authorities gave Belgium-based activist Zanna Vanrenterghem permission to continue to the U.N. climate summit in Katowice early Saturday.

The Belgian ambassador in Poland, Luc Jacobs, said Polish border guards had provided him with no details about the case but confirmed that Vanrenterghem was admitted into Poland overnight.

CAN had no immediate information about 12 other activists deported or denied entry to Poland in recent days.

Environmentalists plan to stage a march Saturday through Katowice, where delegates from almost 200 countries are holding a two-week meeting on curbing climate change.