The Islamic State (Isis) has trained and dispatched at least 400 fighters to Europe to hit the continent in deadly waves. The fanned out network of interlocking terror cells similar to the ones that struck Paris in November and Brussels yesterday have "orders to choose the time, place and method for maximum carnage."

The Associated Press news agency has reported that it spoke to a number of officials, including European and Iraqi intelligence personnel and a French politician, who described camps in Syria, Iraq and possibly even the former Soviet bloc as breeding grounds where jihadis are trained to attack the West.

The news comes just a day after the bloodbath in Brussels on 22 March where more than 30 people were killed and 270 others injured. IS (Daesh) claimed responsibility for the multiple attacks at the Belgian capital's airport and a metro station, saying a "secret cell of soldiers" had been sent to Brussels to commit the atrocities.

The deadly assaults came just four days after the capture of Europe's most wanted man, Salah Abdeslam, a key suspect in the Paris attacks who managed to evade intelligence officials for months. Like Abdeslam, Belgian authorities are hunting at least one fugitive in yesterday's terror attacks.

Describing Abdeslam's movements, French Senator Nathalie Goulet – who is also co-head of a commission tracking jihadi networks – said: "Not only did he drop out of sight, but he did so to organise another attack, with accomplices everywhere. With suicide belts. Two attacks organised just like in Paris. And his arrest, since they knew he was going to talk, it was a response: So what if he was arrested? 'We'll show you that it doesn't change a thing.'"

Officials including Goulet estimate between 400 and 600 fighters have received training to launch external attacks. "The reality is that if we knew exactly how many there were, it wouldn't be happening," she said.

Francophones with ties to North Africa, France and Belgium appear to be heading the units, according to a European security official who wished to remain anonymous. He added that the militants had received training in "battleground strategies, explosives, surveillance techniques and counter surveillance", according to the AP report.

An unidentified senior Iraqi intelligence official said terrorists from the cell that launched the Paris attacks are spread out across a number of European nations, including Germany, Britain, Italy, Denmark and Sweden.