BRUSSELS (REUTERS, AFP) - A van struck a cafe terrace in central Brussels on Friday (Aug 26), leaving six people needing treatment for light injuries and shock and investigators trying to determine whether it was an attack or an accident.

The driver fled in the vehicle after the incident shortly before 1pm local time (7pm Singapore time) and was arrested in the northern city of Antwerp later in the afternoon, Brussels prosecutors told a news conference.

His van had earlier been found abandoned in a nearby Brussels district.

“The facts of course make you think of attacks as have happened in the past, but this is not the only possibility we are considering. It is also possible that it was just an accident,” a Brussels prosecution spokesman said.

None of the injured people needed to be taken to hospital.

One witnesses told Belgian media that the van entered Rue Saint-Michel, which leads into a busy shopping area, with tyres screeching and headed away at high speed.

Video footage of the incident on social media showed the white van indeed travelling quickly and veering wildly, but only brushing the side of the cafe terrace and not obviously targeting people.

Brussels mayor Philippe Close told the daily Le Soir there had been a mixture of tourists and local shoppers on the terrace and that some of the witnesses were in a state of shock.

“What is certain is that the vehicle was travelling at an extremely high speed,” he said.

Belgium’s terrorism tracking Coordination Unit for Threat Analysis (OCAM) briefly raised the threat level in the capital from “medium” to “serious” – from two to three on a scale of four.

But the level was dropped back to medium a few hours later after officials found “reassuring elements in their investigation”, an OCAM spokesman said.