(CNN)Night had just fallen when heavily armed Belgian commandos approached a residence on the Rue des Collines in Verviers, a sleepy town in eastern Belgium. They knew the three men inside -- all suspected to be hardened Belgian ISIS veterans who had returned from fighting in Syria -- were likely to be armed and dangerous because they had put them under 24-hour surveillance for several weeks, according to a senior Belgian counterterrorism official. Wiretaps of phone conversations and listening devices indicated the cell members -- who had been under observation for just under two months and were all from in and around the Molenbeek district of Brussels -- were in the final stages of preparing a major terrorist attack in Belgium, the official told CNN.
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Belgian counterterrorism official tells CNN how they thwarted an ISIS cell
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January 15 was the biggest firefight Belgian commandos have faced since World War II
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The trail goes from Belgium to Greece and Syria
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Belgian investigators are skeptical of that claim and have no evidence to suggest he was able to reach @placeholder.
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The Belgian official said @placeholder was facing an unprecedented terrorist threat with significant concern returning fighters from Syria or ISIS-inspired lone wolves could be plotting attacks.
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The Belgian official said Belgium was facing an unprecedented terrorist threat with significant concern returning fighters from Syria or @placeholder-inspired lone wolves could be plotting attacks.