BRUSSELS • The militant cell behind bombings in Brussels had been plotting to hit France again after carrying out the Paris attacks, but was forced to strike closer to home as police closed in, Belgian prosecutors said yesterday.

"Numerous elements in the investigation have shown that the terrorist group initially had the intention to strike in France again," Belgium's federal prosecutor said in a statement.

"Surprised by the speed of progress in the investigation, they took the decision to strike in Brussels," the prosecutor said.

Investigations into the Islamic State in Iraq and Syria (ISIS) attacks in Paris in November, which killed 130 people, showed that many of the perpetrators lived in Belgium, including surviving suspects who managed to evade police for more than four months.

Prime suspect Salah Abdeslam was arrested by police on March 18 after a shoot-out in the Belgian capital. Four days later, suicide bombers killed 32 people in attacks on Brussels Airport and a rush-hour metro train.

Born and raised in Belgium to Moroccan-born parents, Abdeslam told a magistrate he had planned to blow himself up at a sports stadium in Paris but backed out at the last minute. His brother Brahim blew himself up at a Paris cafe.

Another man linked to the Paris attacks, Mohamed Abrini, was arrested in Brussels last Friday and he has admitted to being the "man in the hat" captured on video walking into Brussels Airport alongside two suicide bombers.

Abrini, 31, has been charged with terrorist murders, prosecutors said.

Another main suspect who was seen alongside the suicide bomber in the Brussels metro and identified by prosecutors as Osama K. was also arrested last Friday in the Belgian capital.

Osama K., 28, widely named by the media as Swedish national Osama Krayem, was filmed buying the bags used to carry the Brussels bombs.

Like Abrini, his fingerprints were found in an apartment used as a bomb factory and safe house for the attackers.

As with other suspects in both the Paris and Brussels attacks, police believe Krayem returned last summer from fighting with ISIS in Syria aboard refugee boats reaching Greek islands.

ISIS wants to carry out attacks in Germany and the security situation is "very serious", the head of the country's domestic intelligence agency, BfV, told a Sunday newspaper, adding that he knew of no concrete plot to strike.

The militant group released a video last Tuesday suggesting it may carry out further attacks in the West after the Brussels bombings and Paris attacks, naming London, Berlin and Rome as possible targets.

Mr Hans-Georg Maassen told German newspaper Welt am Sonntag that the group wanted to carry out attacks against Germany and German interests, but added: "At the moment, we don't have any knowledge of any concrete terrorist attack plans in Germany."

He said ISIS propaganda was aimed at encouraging supporters to take the initiative to stage attacks in Germany.

The US Air Force last Saturday deployed Cold War-era B-52 bombers to bolster the fight against ISIS, stepping up efforts to defeat the extremists. The B-52 Stratofortress aircraft, which arrived in Qatar, were based in Saudi Arabia and last flown operationally in May 2006 as part of the war in Afghanistan, air force officials said.

"The B-52 will provide the coalition continued precision and deliver desired air power effects," said Lieutenant-General Charles Brown, commander of US Air Force's Central Command.

The long-range planes will provide "flexibility and endurance" in the US-led coalition campaign against the extremists, he added.

It was not immediately clear how many of the bombers had been deployed.

REUTERS, AGENCE FRANCE-PRESSE