Police in the city of Verviers, Belgium were fired upon Thursday as they moved in on a suspected terror cell to prevent what they termed an “imminent attack.” No police or civilians were injured in the 15-minute firefight in the city’s crowded train station, where two of the suspected terrorists were killed and a third arrested.

Residents said gunfire and explosions could be heard throughout the city of 56,000, 200 miles from the capital city of Brussels. “These were extremely well-armed men,” said federal magistrate Eric Van cir Sypt, who added that police stations and officers were the targets of the planned attacks. On Friday, Belgium authorities revealed that they seized police uniforms, AK-47s, and Kalishnakov rifles in the suspects’ apartments.

Thursday’s police raid in Belgium was the result of ongoing counter-terror operations and only one of at least 10 police actions carried out throughout the country, including in Brussels. Although authorities said the suspects had been under surveillance for several weeks, the pre-emptive move by police came as Europe remained tense after last week’s attacks at the Paris offices of the satirical newspaper, Charlie Hebdo, and a kosher delicatessen left 17 dead. Belgium officials had not established a direct connection  between the terror cells in Paris and Verviers, but they are pursuing leads suggesting a link between the Verviers cell and Amedy Coulibary, the suspect in the siege at the Jewish deli where four customers and the shooter were killed. Police also said one of the weapons used in the Charlie Hebdo attack may have been purchased in Belgium.

Belgium is only one European country grappling with the increasing threat posed by native-born Muslims who return after fighting in Syria. Once home, the newly-radicalized jihadis establish sleeper cells to wage domestic, guerilla-like attacks on terror targets such as public transportation, including Jewish schools, museums, and shops. The offices and cartoonists of Charlie Hebdo in Paris had been prime targets for years as a result of its publication of cartoons the Muslim jihadists considered blasphemous. Europol, the police force of the European Union (EU),  estimates as many as 5,000 Europeans are currently fighting in Syria, and warns there may be as many 120 sleeper cells throughout Europe.

French authorities announced the arrest of 12 suspected accomplices of the Paris attacks, as terror suspects were taken into custody in Germany, Greece and elsewhere in Belgium in the days following the firefight in Verviers. Although authorities did not confirm that the swift actions by police across Europe were coordinated, the crack downs on sleeper cells and arrests of suspected terrorists underscores the ongoing cooperation between police and Europol in identifying  and preventing  terror attacks throughout the continent.

The firefight in Verviers occurred on the same day the FBI announced the arrest of a 20-year-old man disrupting his plan to bomb the Capitol in Washington DC and kill U.S. officials. Senator Lindsey Graham (R-SC) called the thwarted plot in Belgium “a wake-up call” warning that “it’s just a matter of time if adjustments aren’t made soon.” The budget allocation for intelligence and security, which includes funding for the CIA, has been reduced from $80 million to $63 million in recent years, although Congress is considering increases to in light of the uptick in terror activity in the US, Canada, Australia, England, France and now, Belgium.