Belgium deployed troops in its major cities on Saturday to guard Jewish schools and government buildings, days after police in the country as well as in neighboring France and Germany carried out several counterterrorism operations.

Belgian police raided a group of suspected jihadists on Thursday in which explosives, guns and munitions were seized. A shootout in the city of Verviers left two suspects dead.

Thirteen suspects were arrested altogether and five were charged on Friday with participating in terrorist activities, prosecutors said.

Belgian interior minister Jan Jambon told the BBC a “possible terrorist attack” had been foiled but couldn’t tell if more attacks were likely, “if this is really a network of terrorist cells in Belgium and if they’re going to attack now [or] in the next days.”

Jambon also said some one hundred out of the 350 Belgian nationals who traveled to fight for the Islamic State militant group in Iraq and Syria had returned and were being monitored by the security services.

Defense minister Steven Vandeput said up to three hundred soldiers would be stationed across the country. In Brussels, troops guarded the European Union and NATO headquarters as well as the American and Israeli embassies.

“It’s very important to say that this wasn’t a simple decision,” he told reporters, “but it was necessary, at a time when police are overly engaged, for the army to enter in a supporting role.”

Among other places soldiers were protecting was the Jewish Museum which a lone Islamist gunman targeted in May. Four people were killed at the time.

Troops were also deployed in Antwerp, the country’s second largest city, which has a large Jewish community.

The deployments came ten days after two deadly attacks in Paris in which Islamists attacked a Jewish supermarket and the offices of the Charlie Hebdo satirical newspaper. Seventeen people were killed in those attacks.

No link had yet been established between the terrorist plot in Belgium and the attacks in France.

In Paris on Friday, a gunman took several people hostage at a post office. The siege ended when he gave himself up to police. Gare l’Est was evacuated in a bomb scare the same day. Neither incident

In Germany, two suspects were arrested after raids on twelve homes and a mosque. A police spokesman said the suspects were believed to be part of an extremist cell that recruited fighters for the war in Iraq and Syria.

Belgium and France are both involved in the bombing of Islamic State targets in Iraq. Germany has given weapons to Kurdish peshmerga who are fighting the same group in the country.