BRUSSELS - Belgium has avoided a serious attack, its interior minister said on Wednesday, after a suspected suicide bomber planning to explode a large bomb caused only a minor explosion in Brussels' central station on Tuesday.

Several media outlets reported unnamed sources as saying the device that failed to fully explode was filled with nails and was similar to the bombs used in the attacks at Brussels airport and on the city's metro that killed 32 people last year.

"Yesterday, someone with explosives entered central station. He intended to explode a large bomb. In the end, there was a small explosion to which soldiers reacted immediately. Something much worse has been avoided," Jan Jambon told broadcaster VTM.

The country tightened security even more on Wednesday to counter fears that lone attackers could strike anywhere and at any time.

A federal magistrate said that the suspect, who was shot and killed by soldiers, had Moroccan nationality and wasn't known to authorities for terror activities.

Jambon said police were still investigating the case. He gave no further details on the searches or on why the bomb had not fully exploded.

Prosecutors said on Tuesday that they considered the incident a terrorist attack, although they declined to comment on witness accounts saying the man shouted Islamist slogans before detonating the bomb.

Although no one was hurt, smoke billowing through Central Station sent commuters racing for cover. Police halted rail traffic, evacuated the site and cleared streets crowded with tourists and residents enjoying a hot summer's evening in the city center between the station and nearby Grand Place, Brussels' landmark Renaissance town square.

"We will not let ourselves be intimidated, we will go on living our lives as normal," Belgian Prime Minister Charles Michel said.

The Belgian capital, home to the headquarters of NATO and the European Union, has been on high alert since Brussels-based extremists killed 130 people in Paris in November 2015 and then organized the attack in Brussels months later.

Since then, attacks in France, but also in Germany, Sweden and, most recently, in the United Kingdom, have been carried out in the name of the Islamic State by other young men, many of them locals.

Security experts said Tuesday's incident could have been similar to "lone-wolf" assaults carried out by radicalized individuals with limited access to weapons and training.

"Such isolated acts will continue in Brussels, in Paris and elsewhere. It's inevitable," Brussels security consultant Claude Moniquet, a former French agent, told broadcaster RTL.

With the IS under pressure in Syria - where Belgium has been the most fertile European recruiting ground for foreign extremists - he said attacks in Europe could increase, although many would be by "amateurs" doing little harm.

Reuters - Ap?