French police have arrested a man in the search for a driver who slammed his BMW into soldiers in a Paris suburb, injuring six of them in what appeared to be a carefully timed ambush before speeding away.

The driver’s motive was unclear, but officials said he deliberately aimed at the soldiers, and counterterrorism authorities opened an investigation.

None of the soldiers had life-threatening injuries, authorities said.

It was the latest of several attacks targeting security forces guarding France over the past year.

While others have targeted prominent sites like the Eiffel Tower, Wednesday’s attack hit the leafy, relatively affluent suburb of Levallois-Perret that is home to France’s main intelligence service, the DGSI.

Witnesses described seeing a BMW with one person inside waiting in a cul-de-sac near a building used for the soldiers, according to two police officials.

One official said the attacker struck just as a group of soldiers emerged from the building to board vehicles for a new shift.

French police arrest man suspected of ramming car into soldiers in Paris https://t.co/YabFvCdSNH pic.twitter.com/ScNrcvP7Xh

— CNN Breaking News (@cnnbrk) August 9, 2017

Authorities checked video surveillance of the area, near the city hall of Levallois, northwest of Paris, and police fanned out around the French capital and stopped numerous cars as they searched for the attacker.

Most were released. But in one case, police stopped a car on the A16 highway and arrested the driver and were verifying his possible links to the attack, according to two police officials.

One said the arrest was violent and police fired at the suspect to subdue him. The officials weren’t authorized to be publicly named because of an ongoing police operation.

The street is normally guarded by posts that are removed when vehicles move in and out, so the driver must have known exactly when to strike, Veillant said. “They must’ve really planned this,” he said.

Three of the soldiers hit in the morning attack were slightly injured, while three were more seriously hurt, but their lives weren’t in danger, according to the Defence Ministry.

The defence minister said she received “reassuring” news about their condition Wednesday afternoon.

Six French soldiers injured, two seriously, after vehicle struck them in Paris suburb; search underway for driver https://t.co/u7ndap3f7m pic.twitter.com/RR37vpTQxb

— ABC News (@ABC) August 9, 2017

The soldiers were from the 35th infantry regiment and served in Operation Sentinelle, created to guard prominent French sites after a string of deadly Islamic extremist attacks in 2015.

French counterterrorism prosecutors opened an investigation aimed at pursuing perpetrators on charges of attempted murder of security forces in connection with a terrorist enterprise, the Paris prosecutor’s office said.

The move means authorities believe the attack was deliberate and planned with a terrorist motive.

French President Emmanuel Macron discussed the attack at a previously scheduled top-level security meeting on Wednesday morning.

He has pledged to boost military spending and entrench security measures after a string of Islamic extremist attacks since 2015.