The Belgian military was deployed across several cities to reinforce the country's police on Saturday, including the Belgian capital of Brussels and the northern port city of Antwerp, which has a large Jewish population.

"The mobilized troops will be armed and their primary responsibility will be to survey certain sites," Prime Minster Charles Michel's office said in a statement.

Belgian soldiers could also eventually be deployed in Verviers where two suspected Islamists were killed and a third was wounded by security forces early on Friday during a huge raid on an alleged jihadist cell.

During the same raid, police also detained 13 people, five of whom appeared in court on Friday and were charged with participation in the activities of a terrorist organization.

According to prosecutors, the terrorist cell was planning to kill Belgian police on the streets and in police stations across the country. Several of those arrested had returned from fighting on the side of extremists in Syria.

Continent on high alert

Following Friday's raid, Belgium also increased its terror warning to three - the second highest level - which will remain in place until at least Thursday.

The raids came just a week after terror attacks over three days in Paris which left 17 dead. Although Belgian police said there appeared to be no direct link between the plot in Belgium and the Paris shootings, French Prime Minister Manuel Valls said, "The link that exists is the plan to attack our values."

Like Belgium, several other European nations have also stepped up security in light of last week's attacks on the French satirical magazine Charlie Hebdo and a Paris kosher supermarket.

"Given some of the deliberate targeting of the police we have seen in a number of countries across Europe and the world," said Mark Rowley, head of counter-terrorism for the British police, UK authorities are also mulling "further measures" to protect police.

German police also arrested two people in Berlin on Friday following raids similar to those in Belgium on numerous properties linked to radical Islamic Salafists.

ksb/gsw (AFP, AP, Reuters, dpa)