A a law enforcement official describes Europe's isecurity environment as "difficult."
ເຈົ້າໜ້າທີ່ ສຫລ ແລະ ອີຢູ ເຕືອນເຖິງ ໄພຂົ່ມຂູ່ ຂອງ ພວກກໍ່ການຮ້າຍ
![German police officers patrol the airport terminal in Frankfurt, Germany, Jan. 19, 2015.](https://gdb.voanews.com/c69a19ed-809d-4735-ba9e-5e7197565797_w1024_q10_s.jpg)
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German police officers patrol the airport terminal in Frankfurt, Germany, Jan. 19, 2015.
![A Belgian soldier guards an entrance to the European Council headquarters in central Brussels, Belgium, Jan. 19, 2015.](https://gdb.voanews.com/e7edd355-d1f8-4332-afd5-b56952e492a9_w1024_q10_s.jpg)
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A Belgian soldier guards an entrance to the European Council headquarters in central Brussels, Belgium, Jan. 19, 2015.
![Belgian soldiers patrol the EU headquarters in Brussels, Belgium, Jan. 19, 2015.](https://gdb.voanews.com/11b330dd-5054-4a6a-803a-594604a530bf_w1024_q10_s.jpg)
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Belgian soldiers patrol the EU headquarters in Brussels, Belgium, Jan. 19, 2015.
![In the midst of heightened security, soldiers patrol the EU headquarters in Brussels, Belgium, Jan. 19, 2015.](https://gdb.voanews.com/d1d18cf0-049c-4e66-b686-409d776043be_w1024_q10_s.jpg)
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In the midst of heightened security, soldiers patrol the EU headquarters in Brussels, Belgium, Jan. 19, 2015.