A car ran into and slightly injured a policewoman guarding the French presidential palace Thursday, raising tensions in a country on high alert after the worst terrorist attacks in decades. Funerals are being held for staff killed in the attack on irreverent newspaper Charlie Hebdo amid continued huge demand for its first post-attacks edition.

The incident overnight at the Elysee Palace had no apparent links to last week's shootings and might have been an accident, prosecutors and police said. But it comes at a time when about 120,000 police and other forces are deployed around France as the government seeks to prevent future attacks. Twenty people, including the three gunmen, were killed in last week's rampage.

Officials with Paris police and the presidential palace said in the new incident a car carrying four people took a one-way street in the wrong direction then drove off when the police officer tried to stop them. She sustained slight leg injuries.

Police said two people were later arrested, and two others in the car fled. The officials spoke on condition of anonymity because they were not authorized to be publicly identified.

U.S. and French intelligence officials are leaning toward an assessment that the Paris terror attacks were inspired by al-Qaida but not directly supervised by the group, a view that would put the violence in a category of homegrown incidents that are extremely difficult to detect and thwart.

French justice officials began cracking down by arresting dozens of people who glorified terrorism or made racist or anti-Semitic remarks.

The attacks targeted Charlie Hebdo's offices, a kosher market and police. Charlie Hebdo had been repeatedly threatened for caricatures of the Muslim prophet Muhammad.

Funerals were being held Thursday for at least four Charlie Hebdo contributors killed in the attack.

Customers lined up again Thursday to try to get copies of Charlie Hebdo's first edition since the attacks, which again had Muhammad on the cover. Even though it has a special increased print run of 5 million copies, it sold out before dawn in Paris kiosks for a second day straight.

Muslims believe their faith forbids depictions of the prophet, and some reacted with dismay — and occasional anger — to the new cover. Some who had supported Charlie Hebdo after the attacks felt betrayed and others feared the cartoon would trigger yet more violence.

A leader of Yemen's al-Qaida branch officially claimed responsibility for the attacks by two gunmen that left 12 dead at the weekly publication, saying in a video posted online that the slayings were in "vengeance for the prophet."